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To all customers of the Acton Water District located in Acton, Massachusetts
Arsenic has been detected above Drinking Water Standards

This is an important notice - please translate it for anyone who does not understand English.

This notice is to advise our customers that our water system is in noncompliance with the drinking water treatment standard for arsenic.  Although this is not an emergency, you have a right to know what happened, what you should do, and what we are doing to correct this situation.

We routinely monitor for the presence of drinking water contaminants to monitor the effectiveness of our water treatment system.  Sampling conducted on June 29, 2020 indicated a level of arsenic of 11 parts per billion (ppb) in the treated water, which failed to maintain the level of arsenic concentrations below the standard or maximum contaminant level (MCL) of 10 parts per billion (ppb).  Subsequent sampling during July indicated levels at or below the level detected on June 29th.

What does this mean?

This is not an immediate risk.  If it had been, you would have been notified right away.  Some people who drink water containing arsenic in excess of the MCL over many years could experience skin damage or problems with their circulatory system, and may have an increased risk of getting cancer.  The MCL is based on the average individual consuming 2 liters of water a day for a lifetime.  However, children and pregnant women may be at increased risk and should seek advice from their health care providers if they have any concerns.  Children are at greater risk (to any agent in water) because of their greater water consumption on a per unit body weight basis.  Hand washing, bathing and showering in water that contains arsenic at these levels does not pose a known risk to human health.  Arsenic is not easily absorbed through the skin and does not evaporate into the air. 

Further health information is available from EPA’s Safe Drinking Water Hotline at 1 (800) 426-4791 and at the EPA Arsenic in Drinking water website

What happened?  What is being done?

Arsenic occurs naturally as a contaminant in some groundwater in Massachusetts, most frequently in the central part of the state.  It can also be a by-product of some agricultural and industrial activities.  Drinking water from bedrock wells, also called drilled or artesian wells, gravel developed wells and less frequently from shallow or dug wells, may contain arsenic.

In response to this sampling result, we have increased the frequency of monitoring for arsenic.  Changes to the operation of the filtration system, including the backwashing of the filter media and contributing well sources has been undertaken.  The most recent sample results from July 28th and July 30th were 6 ppb and 5 ppb, respectively.  Both are below the MCL and at a concentration normally seen in treated water.  Our arsenic results in 2019 ranged between 0 and 5 ppb throughout the water system.

Our system will continue to work with MassDEP to ensure future regulatory compliance. 

For more information please contact Chris Allen or Matthew Mostoller at 978-263-9107.

Please share this information with all the other people who drink this water, especially those who may not have received this notice directly (for example, people in apartments, nursing homes, schools, and businesses).  You can do this by posting this notice in a public place or distributing copies by hand or mail.

PWSID#: 2002000                                                             Date Distributed: August 3, 2020