246 active public water systems serve 124,540 people in Merrimack County. 166 are compliant, 80 had at least one EPA violation in the past three years, 1 is a designated serious violator, and 0 carry a health flag.
Active systems24663 community systems
People served125Kby public water systems
Systems with violations8033% of active systems, past 3 years
Serious violators10 systems carry a health flag
Needs attention
Contoocook Village PctNH1191010 · Hopkinton · Community water system · Serves 1,6003 rules violated in the past three years
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 New Hampshire 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.
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.