124 active public water systems serve 627,029 people in Barnstable County. 94 are compliant, 30 had at least one EPA violation in the past three years, 0 are designated serious violators, and 5 carry a health flag.
Active systems12430 community systems
People served627Kby public water systems
Systems with violations3024% of active systems, past 3 years
Serious violators05 systems carry a health flag
Needs attention
Otis Air National Guard BaseMA4096001 · Falmouth · Community water system · Serves 6,0002 rules violated in the past three years. Unresolved: Lead and Copper Rule Revisions (LCRR), TTHM (Total Trihalomethanes), and Total Haloacetic Acids (HAA5).
Block and TackleMA4318055 · Wellfleet · Transient non-community system · Serves 2502 rules violated in the past three years. Unresolved: Public Notification Rule and Revised Total Coliform Rule (RTCR).
The Lobster and Chowder HouseMA4318070 · Wellfleet · Transient non-community system · Serves 2502 rules violated in the past three years. Unresolved: Public Notification Rule and Revised Total Coliform Rule (RTCR).
Winslow TavernMA4318051 · Wellfleet · Transient non-community system · Serves 1853 rules violated in the past three years. Unresolved: Public Notification Rule and Revised Total Coliform Rule (RTCR).
Endless Coast HotelMA4318031 · Wellfleet · Transient non-community system · Serves 642 rules violated in the past three years. Unresolved: Public Notification Rule and Revised Total Coliform Rule (RTCR).
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.