206 active public water systems serve 1,628,657 people in Middlesex County. 121 are compliant, 85 had at least one EPA violation in the past three years, 0 are designated serious violators, and 10 carry a health flag.
Active systems20698 community systems
People served1.6Mby public water systems
Systems with violations8541% of active systems, past 3 years
Serious violators010 systems carry a health flag
Needs attention
Somerville Water Dept. (mwra)MA3274000 · Somerville · Community water system · Serves 81,0451 rule violated in the past three years. Unresolved: Lead and Copper Rule.
Medford Water Dept. (mwra)MA3176000 · Medford · Community water system · Serves 61,7001 rule violated in the past three years. Unresolved: Lead and Copper Rule.
Melrose Water Division (mwra)MA3178000 · Melrose · Community water system · Serves 29,9381 rule violated in the past three years. Unresolved: Lead and Copper Rule.
Stow Acres Country ClubMA2286009 · Stow · Transient non-community system · Serves 3101 rule violated in the past three years. Unresolved: Ground Water Rule.
159 Swanson RD Setra Systems INCMA2037018 · Boxborough · Non-Transient non-community system · Serves 2782 rules violated in the past three years. Unresolved: Lead and Copper Rule and Public Notice Rule and Revised PN Rule.
155 Swanson RD SynqorMA2037024 · Boxborough · Non-Transient non-community system · Serves 1001 rule violated in the past three years. Unresolved: Lead and Copper Rule.
Assurance Technology Corp.MA3051011 · Carlisle · Non-Transient non-community system · Serves 751 rule violated in the past three years. Unresolved: Lead and Copper Rule.
Planet Gymnastics/all Seasons TennisMA2002002 · Acton · Transient non-community system · Serves 751 rule violated in the past three years. Unresolved: Ground Water Rule.
Boxborough Executive Office CenterMA2037019 · Boxborough · Non-Transient non-community system · Serves 601 rule violated in the past three years. Unresolved: Lead and Copper Rule.
Spring Hill WellnessMA2012008 · Ashby · Non-Transient non-community system · Serves 481 rule violated in the past three years. Unresolved: Lead and Copper Rule.
Totals cover active systems. Systems serving more than one county are counted in each county. EPA counts the rules a system was in violation of, not the individual violations; one rule can carry several.
Source: the U.S. EPA's Enforcement and Compliance History Online system (ECHO), which publishes the federal Safe Drinking Water Information System. EPA's terms and values are shown as published. The Massachusetts records are from EPA's data refresh of Oct 7, 2026; EPA refreshes this data quarterly, and states report to EPA with a lag of three to six months, so the newest violations may not appear yet. Retrieved from ECHO on Oct 11, 2026.
Compliant
Compliant
No violations reported to EPA in the past three years.
At least one violation on record with EPA in the past three years. Many are monitoring or reporting lapses rather than contamination; the system page lists which rules were involved and whether each is still open.
EPA's designation, also called an enforcement priority, for a system with unresolved serious, multiple, or continuing violations. EPA expects the system and its state to act quickly to resolve them.
At least one open health-based violation: an exceedance of a maximum contaminant level or residual disinfectant level, or a treatment technique violation. Monitoring and reporting lapses do not raise this flag.