Boston, Massachusetts Water Outage Today

Boston tap water system, by the numbers

Federal records name Boston Water and Sewer Commission as the public water system for Boston, with about 675,647 people on its mains.

What feeds the taps in Boston

Boston does not collect its own raw water. Boston Water and Sewer Commission buys surface water from MWRA and distributes it through its own mains. After treatment the water is held in 1 pump facility, which is the buffer that keeps taps running for a few hours after a pump or main fails.

What this means in an outage. Because the water arrives from MWRA, a break on that supplier's transmission main or a plant shutdown upstream can leave Boston without water even when the local pipes are sound. Watch the supplier's alerts as well as Boston Water and Sewer Commission.

Why the water goes out in Boston

These are the causes that match the record for Boston, listed roughly in order of how much they matter here.

• Freezing weather. Boston sees about 122 days a year with a low at or below 32°F, and 38 days at or below 20°F. The coldest morning in the 2015 through 2025 record came on February 24, 2015. The longest stretch with highs that never rose above freezing ran 27 days, ending February 21, 2015. Frost pushes into shallow service lines first. Mains follow when the ground heaves and thaws, which is why break counts climb a day or two after the temperature swings.
• Older neighborhoods and pipe. 65.1% of occupied homes in Boston were built before 1970, against 35.5% nationally. Streets of that age tend to sit on cast iron and early steel mains that are near or past their design life, which is where most breaks start.
• Tropical storms and hurricanes. Storm surge, flooding and multi-day power cuts are the main threat to treatment plants and pump stations in Massachusetts. Utilities in the region routinely issue precautionary boil notices after a storm, even where nothing is found in the water.
• Flooding and heavy rain. NOAA logged 51 flood, flash flood and heavy rain reports in Suffolk County from 2015 through 2026, and 10 days a year bring an inch of rain or more. Floodwater can undercut pipe crossings, swamp pump stations and overload treatment plants, and a notice to boil water often follows when it enters the system.
• Digging and utility work. Street projects, fiber installation and excavation near buried pipe regularly cut mains in Boston with no warning, usually on a day with perfectly ordinary weather.
• Scheduled work, or a fault inside your own home. Utilities warn customers before a planned shutoff. If nothing was announced and the neighbors are fine, the cause is probably your shutoff valve, meter or pressure regulator.

Boston weather and water-main stress, 2015–2025

Main break season in Boston runs from late fall into early spring, with the coldest stretch around December through February.

These counts come from a gridded reanalysis, which smooths out single-day extremes and can differ by a few degrees from an airport thermometer. Use them to compare seasons and years, not as official station records.

Boil water advisories and the federal violation record for Boston

EPA lists 1 health-based violation for Boston Water and Sewer Commission since 2015.

Most recent health-based entries:

• November 2020: A missed lead service line replacement requirement

When Boston loses pressure after a break or a failed test, Boston Water and Sewer Commission asks affected customers to boil water for drinking and cooking. The notice ends only after samples come back clean, which usually takes one to two days after service returns, and the Massachusetts Department of Environmental Protection (MassDEP) supervises the process.

Lead service lines and old plumbing in Boston

The most recent 90th-percentile lead result filed for Boston Water and Sewer Commission is 5.8 ppb (2026). The federal action level is 15 ppb, so that result is comfortably below it.

The age of the housing matters more than the utility's test average: 65.1% of occupied homes in Boston predate 1970 and 1986 was the year lead pipe and solder were banned. Flush the cold tap after an outage and ask Boston Water and Sewer Commission whether your service line is on its lead inventory.

How long a water outage lasts in Boston

A crew that arrives at an ordinary main break in Boston usually needs 4 to 8 hours to isolate the pipe, dig, repair, flush and restore pressure. Large transmission mains, deep pipes and breaks under busy streets can take a day or more. With 675,647 people on the system, a break on a main that feeds a whole district can leave thousands of homes dry at once, and crews may close valves several blocks away to isolate it.

Ask Boston Water and Sewer Commission for a restoration estimate when you report the outage; for large breaks it is normally posted and updated as the repair progresses.

Preparing for a long water outage in Boston

Census figures put the typical Boston household at about 2.4 people. At one gallon per person per day that is 7 gallons for three days or 33 gallons for a two-week supply.

• 27.8% of homes are in buildings with 20 or more units. Upper floors lose pressure first, and rooftop tanks and booster pumps depend on building power.
• 64.3% of households rent. Tell your landlord or property manager about a leak or outage right away, since the shutoff valve may be theirs.
• Your water heater tank holds 30 to 50 gallons of clean water. Turn off the power or gas to it first, then drain from the valve at the bottom.
• If a planned shutoff or storm is coming, fill the tub and some buckets for flushing toilets and washing; keep drinking water in clean sealed containers.

How Boston compares with nearby water systems

Water outage pages for nearby cities

Cambridge, MA · Lowell, MA · Nashua, NH · Worcester, MA