Information and Frequently Asked Questions about HAA5

Public Notification of Haloacetic Acid (HAA5) Maximum Contaminant Level (MCL) Violation:  January 18, 2019

Notificación Pública de Violación de Niveles Máximos de Contaminantes (MCL) del Ácido Haloacético 5 (HAA5)

What happened?

On January 18, 2019, the Springfield Water and Sewer Commission issued a Tier 2 Public Notification regarding an exceedance of the regulatory limit, also known as the Maximum Contaminant Level (MCL), for haloacetic acid 5 (HAA5).

All customer addresses in Springfield and Ludlow will receive a copy of the public notification in the mail.

This incident was not a public health emergency, but all of our customers were informed in the interest of transparency and in accordance with Massachusetts Department of Environmental Protection’s (MassDEP) Drinking Water Program and EPA’s Safe Drinking Water Act.

What should I do?

There is no immediate public health concern. (If there had been, you would have been informed within 24 hours.) There is nothing you need to do and you may continue to consume and use your water as normal.

What are the health concerns with HAA5?

Some studies have shown that long-term exposure to HAA5 at elevated levels above the MCL over many years may increase the risk of developing health problems, which is why HAA5 is regulated. The MCL is set at a level intended to maintain a large margin of protection against health effects.

People with severe health vulnerabilities or concerns should direct specific health questions to their healthcare provider. More information about the potential health risks of HAA5 is also available from MassDEP, which regulates drinking water quality, at 617-292-5770 or at

Why did this happen?

The MCL for HAA5 is based on a “locational running annual average” (LRAA).  This means the quarterly samples taken at a location over the last 12 months are averaged to determine if HAA5 levels are above or below the regulatory limit. The samples from December 6, 2018, caused the LRAA at three locations in the Commission’s distribution system to exceed the 60 parts per billion (ppb) MCL for HAA5.

HAA5 forms when chlorine reacts with naturally dissolved organic matter found in surface water supplies, such as Cobble Mountain Reservoir. Naturally dissolved organic matter enters the reservoir via rain water and snow melt running off leaves, soil, and other organic material in the surrounding forest.

The above-average rainfall in 2018 increased the amount of naturally dissolved organic matter in the reservoir water by approximately 50%. This resulted in more interaction with chlorine, and thus higher than typical HAA5 levels.

Why is chlorine added to drinking water?

Chlorine has been used in drinking water since the early 1900s to prevent waterborne illness caused by pathogens such as cholera, typhoid, and E. coli. Such pathogens are considered the most widespread and immediate risk to public health associated with drinking water.

The use of chlorine to eliminate waterborne pathogens in drinking water is considered one of the greatest public health achievements of the 20th century. Chlorine is still used by the Commission today to protect the public from the immediate public health risks these pathogens present.

How long will this continue?

The next round of sampling will be complete and an update available after approximately April 1, 2019.

The Commission samples for HAA5 on a quarterly basis, with the last samples taken in December 2018. Quarterly samples from the previous 12 months are averaged at each sample location to determine if they are above or below the MCL.

Customers will be notified if there is an exceedance of the MCL for HAA5 in any given quarter.

What is the Commission doing to resolve the problem?

The Commission is currently evaluating changes to make to its existing treatment processes to reduce HAA5 in the distribution system.

Longer term, the Commission already has a facilities improvement plan underway that will identify long-term treatment upgrades to more effectively remove naturally dissolved organic matter, thus reducing the potential for HAA5 to form. Pilot testing of different treatment methods, which would take place in an isolated model using water from Cobble Reservoir, is also planned.

West Parish Filters Water Treatment Plant was originally built in 1909, with the last major modernization renovation in 1974. Regulation of HAA5 began in the late 1990s. The evolution of scientific knowledge, and new regulations based on that knowledge, highlight the important need for the Commission’s continual investments in water infrastructure improvements.

What if I live in a community that purchases wholesale water from the Commission?

The water departments of Agawam, East Longmeadow, and Longmeadow purchase water on a wholesale basis from the Springfield Water and Sewer Commission. Those communities are responsible for sampling HAA5 in their distribution systems according to their own sample schedules. These communities have the same reporting and notification requirements as the Commission, but corresponding with their respective sampling schedules. Customers in those communities should contact their respective water departments with any questions about notifications they receive about HAA5:

Should I buy a filter to remove HAA5?

No, the water is safe to drink and use as normal. The Commission does not advocate the need to purchase a home water filter to remove HAA5, and does not recommend any particular models or brands.

For customers that still wish to install a home treatment device, it is advised to thoroughly research whether the filter they wish to purchase performs as advertised. According to the American Water Works Association, some forms of home filters can be used to reduce chemical compounds like HAA5. Customers should inquire if the device they choose is certified by an independent third party. NSF International, the Water Quality AssociationUnderwriters Laboratories and CSA International all certify home filter products.

Additional Information

SWSC Executive Director Josh Schimmel and UMass Professor Dr. David Reckhow Discuss HAA5 on Connecting Point – Feb. 12, 2019

Presentation to Springfield City Council Health and Human Services Committee – January 30, 2019

Information for Healthcare Providers

HAA5 Drinking Water Information for Consumers (MassDEP)

MassDEP Drinking Water Program

EPA HAA5 Regulations

HAA5 Test Results for 2018*

* Important:  The regulatory limit for HAA5 is set as an annual average level (known as the “LRAA”) of 60 parts per billion (ppb). A single reading above 60 ppb does not constitute a regulatory violation or health hazard.