On Monday, May 18, 2026, the Manchester Water Works (MWW) will begin a planned six-week hydrant flushing program and chlorine conversion system-wide throughout our five-hundred (500) plus miles of water mains within the MWW water distribution system.
The flushing program will be conducted between the hours of 10:00 p.m. and 6:00 a.m., Sunday through Thursday, in order to minimize inconvenience to customers. Mark Bourque, Deputy Director, Distribution indicates that this annual program is to help improve water quality. The flushing will begin at the Lake Shore Road Water Treatment Plant in east Manchester and progress westerly over the six-week period across the city and areas of the six surrounding towns which MWW serves. Heavy Commercial users will be notified prior to work being done in their immediate area and we request that residential customers with special needs, such as in-house dialysis equipment, call our Department to make their locations known so that they also may be notified in advance of flushing in their area.
Customers may experience a slight discoloration of water during flushing due to increased velocity and reversed flow of the water in the pipelines. MWW regrets that the program may inconvenience some customers, but flushing is a necessary function of the departments’ preventive maintenance program. If you experience discoloration of your water, run cold water from a bathtub or outside spigot for ten to fifteen minutes or until the water clears. If the problem persists, please call the number below.
With questions regarding the chlorine conversion please call (603) 792-2855: flushing program, (603) 792-2807.
Manchester Water Works (MWW) has scheduled a conversion of the disinfectant chloramine used in our water treatment process to chlorine to begin September 2nd and continue through the week of October 14th (six weeks). During this time, you may notice a slight change in the taste and smell of your drinking water that has no harmful effects.
Periodically MWW switches the disinfectant from chloramine to chlorine for the maintenance of our water distribution system. Early on during the conversion, MWW will also conduct selective hydrant flushing to enhance water quality. This procedure is a common practice for many U.S. public water systems that use chloramine as a disinfectant and the practice is approved by the Environmental Protection Agency (EPA) which regulates the safe use of chlorine and chloramine.
MWW routinely collects and tests water samples to monitor for chloramine and chlorine levels throughout the distribution system and will continue to do so during this period. Should you notice a change in the taste or smell of chlorine, MWW recommends:
- Run the cold water tap for two minutes. Run it for five to 10 minutes when water is not used for several hours.
- Refrigerate cold tap water in an open pitcher. Within a few hours, the chlorine taste and odor should dissipate.
- There are available filters that may reduce the chlorine taste and smell. MWW recommends using those that are either installed onto your faucet tap or using a pitcher-style filter. The filter should meet NSF certified safety standards and you should replace the filter as recommended by the manufacturer.
Individuals and business owners who take special precautions to remove chloramine from tap water, such as dialysis centers, medical facilities and aquatic pet owners, should continue to take the same precautions during the temporary switch to chlorine. Most methods for removing chloramine from tap water are effective in removing chlorine. Individuals with special health concerns should consult a health care provider on the use of tap water.
Should you have any concerns, please contact the MWW Laboratory directly at (603) 792-2855 (Monday-Friday, 8:00 a.m. - 4:00 p.m.)
Feasibility Study for Raising the Level of Lake Massabesic by One Foot Ongoing
June 10, 2025
The State of New Hampshire Department of Environmental Service (NHDES) is working closely with the Manchester Water Works and the Turner Group to evaluate the feasibility of raising the dam spillway of Lake Massabesic by one foot.
The purpose of this project is to provide the ability for the lake to store more drinking water for potential future use by New Hampshire communities impacted by drinking water contamination.
Impacts to private property owners and infrastructure are currently being assessed to determine what modifications may be necessary to address potential flooding impacts.
Questions about this project may be directed to watershed@manchesternh.gov.