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Drinking Water - FAQs

Arsenic

What is arsenic?

Arsenic is a metal that occurs naturally in the Earth’s crust in soil, rocks, and minerals. 

How can arsenic get in drinking water?

Arsenic is a byproduct of some agricultural and industrial activities.  It also occurs naturally.  It can enter drinking water through the ground or as run-off into surface water sources.

Why is arsenic in drinking water an important public health issue?

Some people who drink water containing arsenic in excess of the U.S. Environmental Protection Agency’s (EPA) Maximum Contaminant Level (MCL) over many years could experience skin damage or problems with their circulatory system and may have an increased risk of getting cancer.

Specifically, these health effects may include:

  • Thickening and discoloration of the skin, stomach pain, nausea, vomiting, diarrhea, and liver effects;
  • Cardiovascular, pulmonary, immunological, neurological (e.g., numbness and partial paralysis), reproductive, and endocrine (e.g., diabetes) effects;
  • Cancer of the bladder, lungs, skin, kidney, nasal passages, liver, and prostate.

What is a community water system?

A community water system is a type of public water system.  The other type of public water system is a non-community water system.  While all public water systems have at least 15 service connections or serve at least 25 people per day for 60 days of the year, community water systems serve the same people year round and non-community systems do not serve the same people year round.

What is a “Maximum Contaminant Level”?

Community water systems are required to provide drinking water that meets standards established under the Safe Drinking Water Act.  EPA establishes drinking water standards for individual contaminants and groups of contaminants.  In establishing an MCL, EPA evaluates studies on health effects (toxicology and epidemiology), studies on the occurrence of the contaminant in water, and studies on the effectiveness and cost of treatment available to remove the contaminant.  Based on analysis of this information, EPA sets an MCL.

MCLs apply to all community water systems. However, the associated monitoring requirements may vary for a contaminant or contaminant group based on the type of source water and on the results of previous samples.  Regulations and state drinking water agencies specify sample location and acceptable analytical methods.    Surface water systems typically monitor more frequently than groundwater systems because the occurrence of contaminants is more variable over time.  Systems that do not detect contaminants or detect them only at very low levels compared to the MCL monitor less frequently.  Monitoring may also vary based on service population size and water treatment used.

Drinking water standards and monitoring requirements are not static.  New regulations are developed for previously unregulated contaminants.  Also, EPA must periodically review and, if necessary, revise existing regulations based on new information on health effects, treatment, analytical methods, and contaminant occurrence.

What are the monitoring requirements for arsenic?

All community water systems are required to monitor for arsenic at the entry-point to the distribution system; however, the frequency of monitoring varies based on source water type and the level of arsenic observed in past samples.  Routine required monitoring is annual for surface water and once every 3 years for ground water, with quarterly monitoring once a sample exceeds 10 parts per billion (ppb).  With a state granted monitoring waiver, the sampling frequency can be reduced to once every 9 years.

In 2006, the EPA lowered the MCL for arsenic from 50 ppb to 10 ppb (also shown as 10 ug/L).

Are there monitoring requirements for arsenic in private wells?

Local Boards of Health (BOH) have primary jurisdiction over the regulation of private wells. The local BOH is empowered to adopt a private well regulation that establishes criteria for private well siting, construction, water quality, and quantity.

Private well drinking water quality is not included as part of the Massachusetts Environmental Public Health Tracking Program. Residents who obtain water from private wells may obtain additional information from the Massachusetts Department of Environmental Protection by clicking here.

Why is the Massachusetts Department of Public Health tracking arsenic in drinking water?

The U.S. Centers for Disease Control and Prevention (CDC) established nationally consistent environmental and health data measures (NCDM) for the environmental and health tracking network.  Arsenic is an NCDM.  Linking data on arsenic concentrations in drinking water with health data will provide specific information to the general public and policy makers on the degree to which arsenic contamination may be contributing to adverse health impacts in communities throughout the state. 

Atrazine

What is atrazine?

Atrazine is a white, crystalline solid organic compound. It is used in the agricultural industry as an herbicide.

How can atrazine get in drinking water?

Atrazine is sprayed on crops to prevent broadleaf and grassy weeds. It can wash off the soil into streams and groundwater, contaminating well water in nearby areas.

Why is atrazine in drinking water an important public health issue?

Some people who drink water containing atrazine in excess of the U.S. Environmental Protection Agency’s (EPA) Maximum Contaminant Level (MCL) over many years could experience problems with their cardiovascular and reproductive systems.

Specifically, these health effects may include:
  • Congestion of heart, lungs, and kidneys
  • Low blood pressure
  • Muscle spasms
  • Weight loss
  • Damage to adrenal glands
  • Muscular degeneration

What is a community water system?

A community water system is a type of public water system.  The other type of public water system is a non-community water system.  While all public water systems have at least 15 service connections or serve at least 25 people per day for 60 days of the year, community water systems serve the same people year round and non-community systems do not serve the same people year round.

What is a “Maximum Contaminant Level”?

Community water systems are required to provide drinking water that meets standards established under the Safe Drinking Water Act.  EPA establishes drinking water standards for individual contaminants and groups of contaminants.  In establishing an MCL, EPA evaluates studies on health effects (toxicology and epidemiology), studies on the occurrence of the contaminant in water, and studies on the effectiveness and cost of treatment available to remove the contaminant.  Based on analysis of this information, EPA sets an MCL.

MCLs apply to all community water systems. However, the associated monitoring requirements may vary for a contaminant or contaminant group based on the type of source water and on the results of previous samples.  Regulations and state drinking water agencies specify sample location and acceptable analytical methods. Surface water systems typically monitor more frequently than groundwater systems because the occurrence of contaminants is more variable over time.  Systems that do not detect contaminants or detect them only at very low levels compared to the MCL monitor less frequently.  Monitoring may also vary based on service population size and water treatment used.

Drinking water standards and monitoring requirements are not static.  New regulations are developed for previously unregulated contaminants.  Also, EPA must periodically review and, if necessary, revise existing regulations based on new information on health effects, treatment, analytical methods, and contaminant occurrence.

What are the monitoring requirements for atrazine?

In 2003, the EPA initiated a monitoring program for atrazine to focus on exposures through drinking water. Because atrazine is a restricted use pesticide (RUP), the EPA was able to identify where atrazine is used and select only those CWSs with a potential for contamination to be included in the program. These include CWSs that are served by surface water, because atrazine levels are higher in surface water than in groundwater. The CWSs in the program are monitored weekly during the peak-use season and biweekly during the rest of the year. Monitoring is continued for at least 5 years. If a CWS does not exceed the limit during the 5 year period, it is released from the program. However, two exceedances in different years within a 5 year period will result in prohibition of further atrazine use. Water systems can also be added to the program based on data that suggest that those particular systems may reach levels of concern. Because of this, CWSs enter and exit the program on an ongoing basis and the number in the program is different from year to year.

The MCL for atrazine is .003mg/L.

Are there monitoring requirements for atrazine in private wells?

Local Boards of Health (BOH) have primary jurisdiction over the regulation of private wells. The local BOH is empowered to adopt a private well regulation that establishes criteria for private well siting, construction, water quality and quantity.

Private well drinking water quality is not included as part of the Massachusetts Environmental Public Health Tracking Program. Residents who obtain water from private wells may obtain additional information from the Massachusetts Department of Environmental Protection by clicking here.

Why is the Massachusetts Department of Public Health tracking atrazine in drinking water?

The U.S. Centers for Disease Control and Prevention (CDC) established nationally consistent environmental and health data measures (NCDM) for the environmental and health tracking network.  Atrazine is an NCDM.  Linking data on atrazine concentrations in drinking water with health data will provide specific information to the general public and policy makers on the degree to which atrazine contamination may be contributing to adverse health impacts in communities throughout the state. 

Di(2-ethylhexyl) Phthalate (DEHP)

What is DEHP?

DEHP is a colorless liquid that is used in manufacturing as a plasticizer. It is found in many plastic products to make them flexible.

How can DEHP get in drinking water?

Rubber and chemical factories that use DEHP in the manufacturing process can discharge DEHP into the surrounding area. Water systems near waste sites can be contaminated with the discharged chemical.

Why is DEHP in drinking water an important public health issue?

Some people who drink water containing DEHP in excess of the U.S. Environmental Protection Agency’s (EPA) Maximum Contaminant Level (MCL) over many years could experience complications in reproduction and problems with their liver. Prolonged exposure may also increase the risk of developing cancer.

What is a community water system?

A community water system is a type of public water system.  The other type of public water system is a non-community water system.  While all public water systems have at least 15 service connections or serve at least 25 people per day for 60 days of the year, community water systems serve the same people year round and non-community systems do not serve the same people year round.

What is a “Maximum Contaminant Level”?

Community water systems are required to provide drinking water that meets standards established under the Safe Drinking Water Act.  EPA establishes drinking water standards for individual contaminants and groups of contaminants.  In establishing an MCL, EPA evaluates studies on health effects (toxicology and epidemiology), studies on the occurrence of the contaminant in water, and studies on the effectiveness and cost of treatment available to remove the contaminant.  Based on analysis of this information, EPA sets an MCL.

MCLs apply to all community water systems. However, the associated monitoring requirements may vary for a contaminant or contaminant group based on the type of source water and on the results of previous samples.  Regulations and state drinking water agencies specify sample location and acceptable analytical methods.    Surface water systems typically monitor more frequently than groundwater systems because the occurrence of contaminants is more variable over time.  Systems that do not detect contaminants or detect them only at very low levels compared to the MCL monitor less frequently.  Monitoring may also vary based on service population size and water treatment used.

Drinking water standards and monitoring requirements are not static.  New regulations are developed for previously unregulated contaminants.  Also, EPA must periodically review and, if necessary, revise existing regulations based on new information on health effects, treatment, analytical methods, and contaminant occurrence.

What are the monitoring requirements for DEHP?

DEHP was added as a drinking water contaminant by the EPA in 1995. Because of this, it is subject to all EPA drinking water standards as set by the Safe Drinking Water Act of 1986. This law requires the EPA to determine levels of contaminants at which no adverse health effects are expected to occur. These levels are called the maximum contaminant level goals (MCLG), and are not enforceable by the EPA. The maximum contaminant levels (MCLs) are enforceable and set based upon the MCLGs. The EPA attempts to set MCLs that are as close to the health goals as are feasible.

The MCLG for DEHP is zero and the MCL is .006mg/L. This MCL was set based upon the best available science to prevent potential health problems associated with exposure to DEHP. When routine monitoring, required at all water systems, identifies levels of DEHP above the MCL, the water system must take steps to reduce the level. The Public Notification Rule (PN) states that the water provider must also notify their customers within 30 days of the violation and may be required to take additional steps, such as providing an alternate source of drinking water, when serious risk to the health of the public is present. DEHP is also subject to the Toxic Release Inventory (TRI) Program. The TRI provides the public with information on releases of toxic chemicals in their communities. These laws set by the EPA require facilities that use toxic chemicals above specified amounts to report on disposal and release of the chemical annually.

For information on toxic releases in your community, click here.

Are there monitoring requirements for DEHP in private wells?

Local Boards of Health (BOH) have primary jurisdiction over the regulation of private wells. The local BOH is empowered to adopt a private well regulation that establishes criteria for private well siting, construction, water quality, and quantity.

Private well drinking water quality is not included as part of the Massachusetts Environmental Public Health Tracking Program. Residents who obtain water from private wells may obtain additional information from the Massachusetts Department of Environmental Protection by clicking here.

Why is the Massachusetts Department of Public Health tracking DEHP in drinking water?

The U.S. Centers for Disease Control and Prevention (CDC) established nationally consistent environmental and health data measures (NCDM) for the environmental and health tracking network.  DEHP is an NCDM. Linking data on DEHP concentrations in drinking water with health data will provide specific information to the general public and policy makers on the degree to which DEHP contamination may be contributing to adverse health impacts in communities throughout the state. 

Disinfection Byproducts

What are disinfection byproducts (DBPs) and how do they get in drinking water?

Public water may contain viruses and bacteria that can cause illness, such as gastrointestinal disorders or diarrhea.  Public water suppliers disinfect their water to kill these viruses and bacteria.  Chlorine is the most commonly used disinfectant.  Sometimes it is used in combination with other disinfectants, such as ozone, chloramine, chlorine dioxide, and ultraviolet light. 

DBPs are a family of chemicals formed when chlorine-based disinfectants react with naturally occurring organic matter, such as acids from decaying leaves, and other substances in the source water.  The levels of DBPs depend upon the nature of the source water, the type of treatment to remove particles and organic matter, and the type and concentration of chlorine disinfection. 

DBPs include total trihalomethanes (4 chemicals) and haloacetic acids (5 chemicals).

Why are DBPs in drinking water an important public health issue?

When people consume disinfection byproducts at levels exceeding the U.S. Environmental Protection Agency’s (EPA) Maximum Contaminant Level (MCL) over many years, they increase their risk of developing bladder cancer.  Other health effects that may be associated with exposure to DBPs include rectal and colon cancer.  Adverse developmental and reproductive effects associated with exposure to disinfection byproducts during pregnancy are a concern.  They have been studied with mixed results; however, the weight of evidence of the health effects data suggests a potential association.  

What is a community water system?

A community water system is a type of public water system.  The other type of public water system is a non-community water system.  While all public water systems have at least 15 service connections or serve at least 25 people per day for 60 days of the year, community water systems serve the same people year round and non-community systems do not serve the same people year round.

What is a “Maximum Contaminant Level”?

Community water systems are required to provide drinking water that meets standards established under the Safe Drinking Water Act.  EPA establishes drinking water standards for individual contaminants and groups of contaminants.  In establishing an MCL, EPA evaluates studies on health effects (toxicology and epidemiology), studies on the occurrence of the contaminant in water, and studies on the effectiveness and cost of treatment available to remove the contaminant.  Based on analysis of this information, EPA sets an MCL.

MCLs apply to all community water systems. However, the associated monitoring requirements may vary for a contaminant or contaminant group based on the type of source water and on the results of previous samples.  Regulations and state drinking water agencies specify sample location and acceptable analytical methods.    Surface water systems typically monitor more frequently than groundwater systems because the occurrence of contaminants is more variable over time.  Systems that do not detect contaminants or detect them only at very low levels compared to the MCL monitor less frequently.  Monitoring may also vary based on service population size and water treatment used.

Drinking water standards and monitoring requirements are not static.  New regulations are developed for previously unregulated contaminants.  Also, EPA must periodically review and, if necessary, revise existing regulations based on new information on health effects, treatment, analytical methods, and contaminant occurrence.

What are the monitoring requirements for DBPs?

All community water systems that disinfect their water (i.e., all surface water and some groundwater systems) are required to monitor for DBPs in the distribution system.  Monitoring requirements and the number of samples a system collects varies based on source water type, chlorine treatment type, the number of treatment plants, historical DBP levels, and the size of the population served.  Typically, systems with a single treatment plant monitor quarterly at four locations in the distribution system and report the results of samples, quarterly averages, and an annual running average.

Compliance is based on an annual running average of total trihalomethanes at or below 80 parts per billion (ppb) and haloacetic acids at or below 60 ppb.

Are there monitoring requirements for DBPs in private wells?

Local Boards of Health (BOH) have primary jurisdiction over the regulation of private wells. The local BOH is empowered to adopt a private well regulation that establishes criteria for private well siting, construction, water quality and quantity.

Private well drinking water quality is not included as part of the Massachusetts Environmental Public Health Tracking Program. Residents who obtain water from private wells may obtain additional information from the Massachusetts Department of Environmental Protection by clicking here.

Why is the Massachusetts Department of Public Health tracking DBPs in drinking water?

The U.S. Centers for Disease Control and Prevention (CDC) established nationally consistent environmental and health data measures (NCDM) for the environmental and health tracking network. DBPs are an NCDM.  Linking data on DBP concentrations in drinking water with health data will provide specific information to the general public and policy makers on the degree to which DBPs contamination may be contributing to adverse health impacts in communities throughout the state.

Lead

Click here to see the Lead in Drinking Water Factsheet.

What is lead?

Lead is a naturally occurring bluish-gray metal found in small amounts in the earth’s crust.  Lead can be found in all parts of our environment.  Much of it comes from burning fossil fuels, mining, and manufacturing. Lead has many different uses.  It is used in the production of batteries, ammunition, metal products (solder and pipes), and devices to shield X-rays.  It is also a minor constituent in brass plumbing fixtures.  Because of health concerns, lead from paints and ceramic products, caulking, and pipe solder has been dramatically reduced in recent years.  The use of lead as an additive to gasoline in the United States was phased out beginning in 1975.

How does lead get in drinking water?

Typically, lead gets into your water after the water leaves your local treatment plant or your well.  That is, the source of lead in your home's water is most likely from pipes or solder in your home's own plumbing.  The most common cause is corrosion, a reaction between the water and the lead in the pipes or solder.  Dissolved oxygen, low pH (acidity), and low mineral content in water are common causes of corrosion.

Why is lead in drinking water an important public health issue?

For infants and children, exposure to high levels of lead in drinking water can result in delays in physical or mental development.  For adults, it can result in kidney problems or high blood pressure. Although the main sources of exposure to lead are ingesting paint chips and inhaling lead dust, U.S. Environmental Protection Agency (EPA) estimates that 10 to 20 percent of human exposure to lead may come from lead in drinking water.  Infants who consume mostly mixed formula can receive 40 to 60 percent of their exposure to lead from drinking water.  The health effects of lead are most severe for infants and children.

What is a community water system?

A community water system is a type of public water system.  The other type of public water system is a non-community water system.  While all public water systems have at least 15 service connections or serve at least 25 people per day for 60 days of the year, community water systems serve the same people year round and non-community systems do not serve the same people year round.

What is the Lead and Copper Rule?

On June 7, 1991, EPA published a regulation to control lead and copper in drinking water.  This regulation is known as the Lead and Copper Rule (also referred to as the LCR or 1991 Rule).

The rule states that all community water systems are required to monitor for lead in drinking water at customer’s taps.  The number of samples required varies by the size of the population served by the system.  If lead concentrations exceed an action level of 15 ppb in more than 10% of customer taps sampled, the system must undertake a number of additional actions to control corrosion.  The system must also inform the public about steps they should take to protect their health and may have to replace lead service lines under their control.

Are there monitoring requirements for lead in private wells?

Local Boards of Health (BOH) have primary jurisdiction over the regulation of private wells. The local BOH is empowered to adopt a private well regulation that establishes criteria for private well siting, construction, water quality and quantity.

Private well drinking water quality is not included as part of the Massachusetts Environmental Public Health Tracking Program.  Residents who obtain water from private wells may obtain additional information from the Massachusetts Department of Environmental Protection by clicking here.

Why is the Massachusetts Department of Public Health tracking lead in drinking water?

The U.S. Centers for Disease Control and Prevention (CDC) established nationally consistent environmental and health data measures (NCDM) for the environmental and health tracking network. Lead is an NCDM.  Linking data on lead concentrations in drinking water with health data will provide specific information to the general public and policy makers on the degree to which lead contamination may be contributing to adverse health impacts in communities throughout the state.

Nitrates

What are nitrates?

Nitrates and nitrites are nitrogen-oxygen molecules that occur naturally at low levels in water.  Nitrate is the form commonly found in higher levels in water, in areas where nitrogen-based fertilizers are used.  Once taken into the body, nitrates are converted into nitrites.  Nitrates are not normally dangerous to human health unless they are reduced to nitrites.

How do nitrates get in drinking water?

Nitrate and nitrite can enter drinking water sources from nitrate-containing fertilizers, sewage and septic tanks, and decaying natural material such as human waste, livestock manure, and decaying plants.  Nitrate is very soluble in water and moves easily through the soil.  Nitrates and nitrites are likely to remain in water until taken up by plants or consumed by other organisms.

Why are nitrates in drinking water an important public health issue?

High levels of nitrates in drinking water can cause serious illness and sometimes death.  Infants are particularly prone to the effects of nitrate exposure because the body changes nitrates to nitrites, and nitrites subsequently interfere with the oxygen-carrying capacity of the child’s blood by binding to hemoglobin.  This can be an acute condition in which health deteriorates rapidly over a period of days.  Symptoms include shortness of breath and blueness of the skin.

Long term exposures to nitrates and nitrites above the drinking water standard, or Maximum Contaminant Level (MCL) have the potential to cause frequent urination, increased starchy deposits in the kidneys, and hemorrhaging of the spleen.  Long term exposures to nitrates may also cause adverse reproductive effects and some cancers, but these associations are inconclusive at this time.  Presently, health standards are focused on protecting infants.

What is a community water system?

A community water system is a type of public water system.  The other type of public water system is a non-community water system.  While all public water systems have at least 15 service connections or serve at least 25 people per day for 60 days of the year, community water systems serve the same people year round and non-community systems do not serve the same people year round. 

What is a “Maximum Contaminant Level”, or MCL?

Community water systems are required to provide drinking water that meets standards established under the Safe Drinking Water Act.  The U.S. Environmental Protection Agency (EPA) establishes drinking water standards for individual contaminants and groups of contaminants.  In establishing an MCL, EPA evaluates studies on health effects (toxicology and epidemiology), studies on the occurrence of the contaminant in water, and studies on the effectiveness and cost of treatment available to remove the contaminant.  Based on analysis of this information, EPA sets an MCL.  

MCLs apply to all community water systems. However, the associated monitoring requirements may vary for a contaminant or contaminant group based on the type of source water and on the results of previous samples.  Regulations and state drinking water agencies specify sample location and acceptable analytical methods.    Surface water systems typically monitor more frequently than groundwater systems because the occurrence of contaminants is more variable over time.  Systems that do not detect contaminants or detect them only at very low levels compared to the MCL monitor less frequently.  Monitoring may also vary based on service population size and water treatment used.

Drinking water standards and monitoring requirements are not static.  New regulations are developed for previously unregulated contaminants.  Also, EPA must periodically review and, if necessary, revise existing regulations based on new information on health effects, treatment, analytical methods, and contaminant occurrence.

What are the monitoring requirements for nitrates?

All public water systems are required to monitor for nitrates at each entry-point to the distribution system.  However, the frequency of monitoring varies based on source water type and the levels of nitrate and nitrite observed in past samples.  Required routine monitoring is annual for ground water sources (or quarterly if a sample exceeds half the MCL) and quarterly for surface water sources (or annual if 4 consecutive quarterly results for the system are less than half of the MCL).

EPA has set MCL drinking water standards of 10 mg/L for total nitrate and nitrite; 10 mg/L for nitrate and 1 mg/L for nitrite.

Are there monitoring requirements for nitrates in private wells?

Local Boards of Health (BOH) have primary jurisdiction over the regulation of private wells. The local BOH is empowered to adopt a private well regulation that establishes criteria for private well siting, construction, water quality, and quantity.

Private well drinking water quality is not included as part of the Massachusetts Environmental Public Health Tracking Program. Residents who obtain water from private wells may obtain additional information from the Massachusetts Department of Environmental Protection by clicking here.

Why is the Massachusetts Department of Public Health tracking nitrates in drinking water?

The U.S. Centers for Disease Control and Prevention (CDC) established nationally consistent environmental and health data measures (NCDM) for the environmental and health tracking network.  Nitrates are an NCDM.  Linking data on nitrate concentrations in drinking water with health data will provide specific information to the general public and policy makers on the degree to which nitrate contamination may be contributing to adverse health impacts in communities throughout the state.

Tetrachloroethene (Tetrachloroethylene) (PCE)

What is tetrachloroethene?

Tetrachloroethene is a colorless liquid that is used in dry-cleaning and for metal degreasing.

How can tetrachloroethene get in drinking water?

Tetrachloroethene is introduced to drinking water sources through waste and discharge from factories or dry cleaners that use the chemical.

Why is tetrachloroethene in drinking water an important public health issue?

Some people who drink water containing tetrachloroethene in excess of the U.S. Environmental Protection Agency’s (EPA) Maximum Contaminant Level (MCL) over many years could experience problems with their liver or an increased risk of getting cancer.

What is a community water system?

A community water system is a type of public water system.  The other type of public water system is a non-community water system.  While all public water systems have at least 15 service connections or serve at least 25 people per day for 60 days of the year, community water systems serve the same people year round and non-community systems do not serve the same people year round.

What is a “Maximum Contaminant Level”?

Community water systems are required to provide drinking water that meets standards established under the Safe Drinking Water Act. EPA establishes drinking water standards for individual contaminants and groups of contaminants.  In establishing an MCL, EPA evaluates studies on health effects (toxicology and epidemiology), studies on the occurrence of the contaminant in water, and studies on the effectiveness and cost of treatment available to remove the contaminant.  Based on analysis of this information, EPA sets an MCL.

MCLs apply to all community water systems. However, the associated monitoring requirements may vary for a contaminant or contaminant group based on the type of source water and on the results of previous samples.  Regulations and state drinking water agencies specify sample location and acceptable analytical methods.    Surface water systems typically monitor more frequently than groundwater systems because the occurrence of contaminants is more variable over time.  Systems that do not detect contaminants or detect them only at very low levels compared to the MCL monitor less frequently.  Monitoring may also vary based on service population size and water treatment used.

Drinking water standards and monitoring requirements are not static.  New regulations are developed for previously unregulated contaminants.  Also, EPA must periodically review and, if necessary, revise existing regulations based on new information on health effects, treatment, analytical methods, and contaminant occurrence.

What are the monitoring requirements for tetrachloroethene?

The EPA recognizes PCE as a toxic contaminant of drinking water. Because of this, it is subject to all EPA drinking water standards as set by the Safe Drinking Water Act of 1986. This law requires the EPA to determine levels of contaminants at which no adverse health effects are expected to occur. These levels are called the maximum contaminant level goals (MCLG), and are not enforceable by the EPA. The maximum contaminant levels (MCL’s) are enforceable and set based upon the MCLG’s. The EPA attempts to set MCL’s that are as close to the health goals as are feasible.

The MCLG for tetrachloroethene is zero and the MCL is .005mg/L. When routine monitoring, required at all water systems, identifies levels of tetrachloroethene above the MCL, the water system must take steps to reduce the level. The Public Notification Rule (PN) states that the water provider must also notify their customers within 30 days of the violation and may be required to take additional steps, such as providing an alternate source of drinking water, when serious risk to the health of the public is present.

Are there monitoring requirements for tetrachloroethene in private wells?

Local Boards of Health (BOH) have primary jurisdiction over the regulation of private wells. The local BOH is empowered to adopt a private well regulation that establishes criteria for private well siting, construction, water quality, and quantity.

Private well drinking water quality is not included as part of the Massachusetts Environmental Public Health Tracking Program. Residents who obtain water from private wells may obtain additional information from the Massachusetts Department of Environmental Protection by clicking here.

Why is the Massachusetts Department of Public Health tracking tetrachloroethene in drinking water?

The U.S. Centers for Disease Control and Prevention (CDC) established nationally consistent environmental and health data measures (NCDM) for the environmental and health tracking network.  Tetrachloroethene is an NCDM. Linking data on tetrachloroethene concentrations in drinking water with health data will provide specific information to the general public and policy makers on the degree to which tetrachloroethene contamination may be contributing to adverse health impacts in communities throughout the state.

Trichloroethene (Trichloroethylene) (TCE)

What is trichloroethene?

Tricholorethene is a colorless or blue liquid that is used in metal-degreasing and in the production of textiles.

How can trichloroethene get in drinking water?

Tricholorethene is introduced to drinking water sources through waste and discharge from factories where it is used.

Why is trichloroethene in drinking water an important public health issue?

Some people who drink water containing trichloroethene in excess of the U.S. Environmental Protection Agency’s (EPA) Maximum Contaminant Level (MCL) over many years could experience problems with their liver or an increased risk of getting cancer.

What is a community water system?

A community water system is a type of public water system.  The other type of public water system is a non-community water system.  While all public water systems have at least 15 service connections or serve at least 25 people per day for 60 days of the year, community water systems serve the same people year round and non-community systems do not serve the same people year round.

What is a “Maximum Contaminant Level”?

Community water systems are required to provide drinking water that meets standards established under the Safe Drinking Water Act.  EPA establishes drinking water standards for individual contaminants and groups of contaminants.  In establishing an MCL, EPA evaluates studies on health effects (toxicology and epidemiology), studies on the occurrence of the contaminant in water, and studies on the effectiveness and cost of treatment available to remove the contaminant.  Based on analysis of this information, EPA sets an MCL.

MCLs apply to all community water systems. However, the associated monitoring requirements may vary for a contaminant or contaminant group based on the type of source water and on the results of previous samples.  Regulations and state drinking water agencies specify sample location and acceptable analytical methods.    Surface water systems typically monitor more frequently than groundwater systems because the occurrence of contaminants is more variable over time.  Systems that do not detect contaminants or detect them only at very low levels compared to the MCL monitor less frequently.  Monitoring may also vary based on service population size and water treatment used.

Drinking water standards and monitoring requirements are not static.  New regulations are developed for previously unregulated contaminants.  Also, EPA must periodically review and, if necessary, revise existing regulations based on new information on health effects, treatment, analytical methods, and contaminant occurrence.

What are the monitoring requirements for trichloroethene?

The EPA recognizes TCE as a toxic contaminant of drinking water. Because of this, it is subject to all EPA drinking water standards as set by the Safe Drinking Water Act of 1986. This law requires the EPA to determine levels of contaminants at which no adverse health effects are expected to occur. These levels are called the maximum contaminant level goals (MCLG), and are not enforceable by the EPA. The maximum contaminant levels (MCL’s) are enforceable and set based upon the MCLG’s. The EPA attempts to set MCL’s that are as close to the health goals as are feasible.

The MCLG for trichloroethene is zero and the MCL is .005mg/L. When routine monitoring, required at all water systems, identifies levels of trichloroethene above the MCL, the water system must take steps to reduce the level. The Public Notification Rule (PN) states that the water provider must also notify their customers within 30 days of the violation and may be required to take additional steps, such as providing an alternate source of drinking water, when serious risk to the health of the public is present.

Are there monitoring requirements for trichloroethene in private wells?

Local Boards of Health (BOH) have primary jurisdiction over the regulation of private wells. The local BOH is empowered to adopt a private well regulation that establishes criteria for private well siting, construction, water quality, and quantity.

Private well drinking water quality is not included as part of the Massachusetts Environmental Public Health Tracking Program. Residents who obtain water from private wells may obtain additional information from the Massachusetts Department of Environmental Protection by clicking here.

Why is the Massachusetts Department of Public Health tracking trichloroethene in drinking water?

The U.S. Centers for Disease Control and Prevention (CDC) established nationally consistent environmental and health data measures (NCDM) for the environmental and health tracking network.  Trichloroethene is an NCDM.  Linking data on trichloroethene concentrations in drinking water with health data will provide specific information to the general public and policy makers on the degree to which trichloroethene contamination may be contributing to adverse health impacts in communities throughout the state. 

Uranium

What is uranium?

Uranium is a naturally-occurring radioactive metal that is found naturally in the environment.

How can uranium get in drinking water?

Uranium occurs at naturally high levels in certain geographic locations in the US. In these locations, uranium contaminates groundwater that is surrounded by affected rock and soil.

Why is uranium in drinking water an important public health issue?

People who drink water containing uranium in excess of the U.S. Environmental Protection Agency’s (EPA) Maximum Contaminant Level (MCL) over many years will experience increased exposure to radiation, which may lead to certain types of cancer.

What is a community water system?

A community water system is a type of public water system.  The other type of public water system is a non-community water system.  While all public water systems have at least 15 service connections or serve at least 25 people per day for 60 days of the year, community water systems serve the same people year round and non-community systems do not serve the same people year round.

What is a “Maximum Contaminant Level”?

Community water systems are required to provide drinking water that meets standards established under the Safe Drinking Water Act.  EPA establishes drinking water standards for individual contaminants and groups of contaminants.  In establishing an MCL, EPA evaluates studies on health effects (toxicology and epidemiology), studies on the occurrence of the contaminant in water, and studies on the effectiveness and cost of treatment available to remove the contaminant.  Based on analysis of this information, EPA sets an MCL.

MCLs apply to all community water systems. However, the associated monitoring requirements may vary for a contaminant or contaminant group based on the type of source water and on the results of previous samples.  Regulations and state drinking water agencies specify sample location and acceptable analytical methods.    Surface water systems typically monitor more frequently than groundwater systems because the occurrence of contaminants is more variable over time.  Systems that do not detect contaminants or detect them only at very low levels compared to the MCL monitor less frequently.  Monitoring may also vary based on service population size and water treatment used.

Drinking water standards and monitoring requirements are not static.  New regulations are developed for previously unregulated contaminants.  Also, EPA must periodically review and, if necessary, revise existing regulations based on new information on health effects, treatment, analytical methods, and contaminant occurrence.

What are the monitoring requirements for uranium?

Uranium is monitored only in community water systems. Because of the wide variation in uranium levels based on geographic location, levels may vary within a water system. According to the Radionuclides Rule, established by the EPA in 2000, all water entering the distribution system must be tested. The MCL for uranium in drinking water is .03 mg/L.

Are there monitoring requirements for uranium in private wells?

Local Boards of Health (BOH) have primary jurisdiction over the regulation of private wells. The local BOH is empowered to adopt a private well regulation that establishes criteria for private well siting, construction, water quality, and quantity.

Private well drinking water quality is not included as part of the Massachusetts Environmental Public Health Tracking Program. Residents who obtain water from private wells may obtain additional information from the Massachusetts Department of Environmental Protection by clicking here.

Why is the Massachusetts Department of Public Health tracking uranium in drinking water?

The U.S. Centers for Disease Control and Prevention (CDC) established nationally consistent environmental and health data measures (NCDM) for the environmental and health tracking network.  Uranium is an NCDM. Linking data on uranium concentrations in drinking water with health data will provide specific information to the general public and policy makers on the degree to which uranium contamination may be contributing to adverse health impacts in communities throughout the state. 
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