Tapcensus

Water quality in Half Moon Bay, California

Half Moon Bay is in San Mateo County. 51 active public water systems serve the county; 15 had an EPA violation in the past three years.

Most likely your provider

Coastside County Water District CA4110011 · Community water system · Surface water
Serves 19,033 people Rules violated, past 3 years 0 Last sanitary survey Jul 26, 2023 Distance 0.3 mi

Your location is within the outer bounds of this system's EPA service area.

View system details EPA facility report

Other community water systems in San Mateo County

35 systems, nearest first
SystemServesStatusRules violated, 3 yrDistance
Montara Water and Sanitary District
 6,088 0 6.3 mi
Town of Hillsborough
 11,766 0 7.7 mi
California Water Service San Mateo
 103,536 0 8.7 mi
Mid-Peninsula Water District
 31,059 0 8.7 mi
City of Burlingame
Burlingame		 32,453 0 9.1 mi
City of Millbrae
Millbrae		 22,795 1 9.4 mi
California Water Service Bear Gulch
 60,382 0 9.6 mi
California Water Service San Carlos
 34,801 0 9.6 mi
North Coast County Water Dist
 38,546 0 10.0 mi
City of San Bruno
San Bruno		 42,631 0 10.9 mi
Estero Municipal Improvement District
 36,556 0 11.2 mi
City of Redwood City
Redwood City		 90,043 0 11.5 mi
Westborough Water District
 13,486 0 12.2 mi
Redwood Terrace Mutual
 56 1 13.3 mi
California Water Service-S San Francisco
 62,609 0 13.4 mi
Cuesta la Honda Guild INC
 863 0 13.9 mi
Menlo Park Municipal Water
Menlo Park		 22,362 0 14.5 mi
County Service Area 7
 300 1 14.7 mi
County Service Area 11
 450 0 15.2 mi
City of Daly City
Daly City		 102,593 0 15.2 mi
Loma Mar Mutual
 65 0 15.4 mi
Camp Jones Gulch
 44 0 15.5 mi
City of Brisbane
Brisbane		 3,434 0 15.5 mi
Guadalupe Valley Mid
 1,455 0 15.6 mi
Marchi Central Farm
 30 2 15.7 mi
All 36 community water systems in San Mateo County
Non-community systems in San Mateo County (15: schools, campgrounds, workplaces, restaurants)

These systems serve places you visit rather than homes.

SystemServesStatusRules violated, 3 yrUnresolved
Skylawn Memorial Park (skylawn Inc)
 50 1 1
UC Elkus Ranch
 34 0 0
Martins Beach Water System
 49 1 0
San Gregorio Company
 32 1 0
Optimists Volunteers for Youth
 205 1 0
LA Honda Center
 33 0 0
Harley Farms Goat Dairy
 113 0 0
San Mateo County Memorial Park
 1,790 0 0
Butano Girl Scout Camp
 154 0 0
Butano State Park Csp
 121 0 0
Csp Portola State Park
 172 0 0
Pigeon Point Hostel
 67 1 1
Gazos Creek Beach House
 33 0 0
Costanoa Campground
 33 1 0
Csp Ano Nuevo State Park
 709 0 0
About this data

Water systems are matched to San Mateo County, nearest to Half Moon Bay first. Your exact provider depends on your address and connection; the largest community water system in a county is usually the city or town utility. Distances are measured to the centre of the service area EPA publishes for the system.

Town locations and ZIP code areas come from U.S. Census Bureau 2020 files.

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 California 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.