Total Trihalomethanes (TTHMs)

Update: The Town of Westminster Has Achieved Tier 2 Compliance for Total Trihalomethanes

The Town of Westminster Water Department is pleased to announce that we have achieved compliance and are no longer in violation of a Tier 2 Massachusetts Drinking Water Regulation. Together, our team of water professionals executed a plan to reduce the locational running annual average (LRAA) for total trihalomethanes (TTHM) in the public drinking water supply, including flushing the water distribution system, and continually sampling and monitoring the levels of TTHM in the water to ensure our actions were having an impact and to protect public health and safety.

What Happened?

TTHMs are a group of disinfection byproducts that form when chlorine compounds, which are used to disinfect water, react with other naturally occurring chemicals in the water. They are colorless and will evaporate out into the air. There are four significant TTHM (chloroform, bromoform, bromodichloromethane, and dibromochloromethane) potentially found in disinfected drinking water and their combined concentration is referred to as total TTHM.

We will continue to monitor the public drinking water supply for all regulated inorganic substances, synthetic organics, volatile organic compounds (vocs), Total Coliform, e.coli bacteria, unregulated (secondary) substances, organic disinfection byproducts, radionuclides, as well as lead and copper. Our team is committed to providing clean, safe water. As stewards of this valuable resource, we take our job to protect public health and safety seriously. Our team of 30+ professionals work around the clock to provide reliable, cost-effective, high-quality water service that protects public health, promotes environmental stewardship, maintains customer confidence, and supports economic development and sustainability.

Recent TTHM Sampling Results

Definitions

• Parts Per Billion (PPB)
• Maximum Contaminant Level (MCL)
• Running Annual Average (RAA): Average of one year of consecutive compliance periods, including the current one.
• Location Running Annual Average (LRAA): RAA from the same sample location. Average of this quarter and three prior consecutive quarterly averages at the same location. 
• Operational Evaluation Level (OEL): Average of the two previous quarter’s results and twice the current quarter’s results.

What can you do to reduce exposure?  

• Some activated carbon type filters can help remove or lower chlorine and TTHM levels. For more information on filters please refer to US EPA Filtration Facts at https://www.epa.gov/sites/default/files/2015-11/documents/2005_11_17_faq_fs_healthseries_filtration.pdf
• The CDC also has information on water filtration options for your home: 
  • Choosing Home Water Filters & Other Water Treatment Systems 
  • A Guide to Drinking Water Treatment Technologies for Household Use
  • Drinking Water Treatment Technologies for Household Use (PDF)
• Use bottled water for drinking. 

Where to find more information? 

• Frequently Asked Questions About Total Trihalomethanes (PDF) 
• A question-and-answer document on health effects, precautions, and water treatment options for TTHMs is available on the MassDEP website.  https://www.mass.gov/service-details/tthm-in-drinking-water-information-for-consumers 
• You can also contact the US EPA Safe Drinking Water Hot Line at #1-800-426-4791. 
• Should you have any questions, you may speak with a water quality representative by calling (800) 604-8717 or by emailing us at waterquality@westminster-ma.gov