Information and Frequently Asked Questions about HAA5

Public Notification of Haloacetic Acid (HAA5) Maximum Contaminant Level (MCL) Violation (April 5, 2019)

Notificación Pública de Violación de Niveles Máximos de Contaminantes (MCL) del Ácido Haloacético 5 (HAA5)  (April 5, 2019)

What is this notification?

On April 5, 2019, the Springfield Water and Sewer Commission issued a Tier 2 Public Notification about an exceedance of the regulatory limit, also known as the Maximum Contaminant Level (MCL), for haloacetic acid 5 (HAA5). This public notification is based on sample results from March 2019.

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

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.  You may continue to consume and use your water as normal.

You do not need to drink bottled water.

You do not need to boil the water. (Boiling the water will have no effect on HAA5, as it is not a microorganism.)

Should I install 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 choose performs as advertised. According to the American Water Works Association, some home filters can be used to reduce some chemical compounds that form due to chlorination, but not all. Customers should inquire if the device they choose is certified by an independent third party. NSF International, the Water Quality Association, and Underwriters Laboratories all certify home filter products.

Why is HAA5 regulated?

Some studies have shown that long-term exposure to HAA5 at elevated levels above the regulatory limit over many years (i.e. a lifetime) may increase the risk of developing health problems. The MCL is set at a level intended to maintain a large margin of protection against health effects.

People with severe or acute health vulnerabilities or conditions 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

Additional information on why HAA5 is regulated is discussed by Dr. David Reckow on Connecting Point (Feb. 12, 2019):  See the video

Why did this happen (again)?

HAA5 forms when chlorine reacts with dissolved natural organic matter (NOM) found in surface water supplies, such as Cobble Mountain Reservoir. Dissolved natural organic matter enters the reservoir from rain and snow melt from the surrounding forest.

The above-average rainfall in 2018 increased the amount of dissolved NOM in the reservoir water by approximately 50%. This resulted in more interaction with chlorine, and thus higher than typical HAA5 levels. Though NOM levels are decreasing, the Commission’s water treatment plant was not designed to remove NOM at these elevated 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 (bacteria) 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 has been used by the Commission since 1966. The regulatory limit for HAA5 is set at a level that considers and balances the immediate health risk presented by waterborne pathogens should the water not be adequately disinfected, and the long-term health risks presented by HAA5 after long-term (decades or a lifetime) exposure to elevated levels.

How long will this continue?

Though HAA5 levels generally decreased since December, the Commission expects exceedances of the HAA5 regulatory limit to persist at least through 2019. This is in part because the regulatory limit for HAA5 is calculated as a running annual average. Elevated results from December 2018 and March 2019 will thus factor into future compliance calculations.

To calculate compliance, samples taken at the same location over the last 12 months are averaged together to determine if HAA5 levels are above or below the regulatory limit of 60 parts per billion (ppb). The samples from March 6, 2019, caused the LRAA at five out of eight locations in the Commission’s distribution system to average above 60 ppb.

The Commission samples for HAA5 on a quarterly basis. The next round of sampling will be complete in June. Customers will be notified if there is an exceedance of the HAA5 MCL at any sample location in any given quarter.

What if I live near one of the elevated sample locations?

The public notice is relevant to all retail customers in Springfield and Ludlow. HAA5 levels can fluctuate throughout the distribution system and being closer to/farther from a sample station with elevated levels does not increase/decrease risk.

What is the Commission doing to resolve the problem?

In order to reduce HAA5 levels in the distribution system, the Commission has modified its existing treatment processes to the extent feasible to remove as much dissolved natural organic matter as possible.

A comprehensive plan for the water treatment plant has been underway for two years, partly in anticipation of the potential for this issue. A $70 million plan for system upgrades, which will address HAA5 through more effective NOM removal, has been initiated and will be designed and built over the next four years. These upgrades include:

    • 60 MGD Dissolved Air Floatation (DAF) Clarification Process – to remove suspended particles prior to filtration
    • Rapid Sand Filter Upgrades – to more effectively filter out NOM
    • New Electrical System – to support new treatment processes
    • New Chemical Storage and Feed Building – to support new treatment processes

Pilot testing of the above selected treatment methods, which would take place in an isolated model using water from Cobble Reservoir, is also planned for 2019-2020.

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.

(Please call Jaimye Bartak, Communications Manager, at 413-452-1302 or if you have any questions about these planned solutions.)

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:


Commission customers with questions about this public notification should call 413-310-3501 or email

The Commission also provided information on HAA5 and planned solutions at the following events (presentations are available below):

  • City Council Health and Human Services Committee:  Tuesday, April 9, 5 PM, City Hall Room 200
  • Public Information Session on HAA5 and Planned Solutions:  Monday, April 22, 6 PM, City Hall Room 220

Additional Information

HAA5 Public Information Session Presentation – April 22, 2019

Presentation to City Council Health and Human Services Committee – Update on HAA5 – April 9, 2019

HAA5 Drinking Water Information for Consumers (MassDEP)

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

MassDEP Drinking Water Program

EPA HAA5 Regulations

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

Notificación Pública de Violación de Niveles Máximos de Contaminantes (MCL) del Ácido Haloacético 5 (HAA5)  (Archivo: January 18, 2019)

HAA5 Test Results – December 2018*

HAA5 Test Results – March 2019*

* 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.