San Mateo County, California Water Systems

San Mateo County, California

60 community water systems on record — 36 active, 24 inactive.

Every active community water system nationwide must produce a Consumer Confidence Report under the EPA's revised rule, effective for reports due July 1, 2027.

Data sourced from the EPA ECHO database (SDWA bulk download), last refreshed July 4, 2026. This is a record-keeping and public-information tool — it does not replace California’s official records. Always confirm current status with California before making decisions based on this information.

Community water systems in San Mateo County, California

System name	City	Population served	Status
AMESPORT MUTUAL WATER COMPANY	HALF MOON BAY	25	Inactive
ANO NUEVO FLOWER GROWERS	DALY CITY	36	Inactive
AUSTIN CREEK - BLOCK 5 & 6	SAN BRUNO	30	Inactive
BIANCHI FLOWERS INC	PESCADERO	65	Active
BUTANO CANYON MUTUAL	PESCADERO	150	Active
CALIFORNIA GOLF CLUB	S SAN FRANCISCO	25	Inactive
CALIFORNIA WATER SERVICE - BEAR GULCH	SAN JOSE	61,431	Active
CALIFORNIA WATER SERVICE - SAN CARLOS	SAN JOSE	35,344	Active
CALIFORNIA WATER SERVICE - SAN MATEO	SAN JOSE	102,348	Active
CALIFORNIA WATER SERVICE-S SAN FRANCISCO	SAN JOSE	64,146	Active
CAMP JONES GULCH	LA HONDA	357	Active
CAMP LOMA MAR	OAKLAND	208	Active
CITY OF BRISBANE	BRISBANE	3,402	Active
CITY OF BURLINGAME	BURLINGAME	31,451	Active
CITY OF DALY CITY	DALY CITY	104,901	Active
CITY OF EAST PALO ALTO	EAST PALO ALTO	29,519	Active
CITY OF MILLBRAE	MILLBRAE	22,795	Active
CITY OF REDWOOD CITY	REDWOOD CITY	92,819	Active
CITY OF SAN BRUNO	SAN BRUNO	42,631	Active
COASTSIDE COUNTY WATER DISTRICT	HALF MOON BAY	18,940	Active
CORDILLERS MUTUAL WATER COMPANY	Redwood City	59	Inactive
COUNTY SERVICE AREA 11	REDWOOD CITY	642	Active
COUNTY SERVICE AREA 7	REDWOOD CITY	300	Active
CROCKER CURVE WATER CO	A 94020	15	Inactive
CUESTA LA HONDA GUILD INC	LA HONDA	915	Active
DEARBORNE PARK WATER SYSTEM	—	45	Inactive
DIMOND PUBLIC UTILITY DIST	DALY CITY	725	Inactive
DURARTE'S WATER SYSTEM	PESCADERO	34	Inactive
ESTERO MUNICIPAL IMPROVEMENT DISTRICT	FOSTER CITY	36,556	Active
GUADALUPE VALLEY MID	BRISBANE	1,472	Active
KINGS MOUNTAIN PARK MUTUAL	WOODSIDE	66	Inactive
LA HONDA PROPERTIES	MENLO PARK	50	Inactive
LOMA MAR MUTUAL	LOMA MAR	65	Active
LOS TRANCOS WD	PORTOLA VALLEY	0	Inactive
MAINTENANCE DISTRICT	SAN MATEO	110	Inactive
MARCHI CENTRAL FARM	PESCADERO	50	Active
MENLO COLLEGE	ATHERTON	850	Inactive
MENLO PARK MUNICIPAL WATER	MENLO PARK	22,362	Active
MID-PENINSULA WATER DISTRICT	BELMONT	30,609	Active
MONTARA WATER AND SANITARY DISTRICT	MONTARA	6,078	Active
NORTH COAST COUNTY WATER DIST	PACIFICA	38,546	Active
O'CONNOR TRACT CO-OPERATIVE WATER CO.	PALO ALTO	2,789	Active
OKU INCORPORATED	PESCADERO	35	Active
PALO ALTO PARK MUTUAL WATER COMPANY	EAST PALO ALTO	2,900	Active
PILLAR RIDGE MHP (FORMER EL GRANADA MHP)	MOSS BEACH	1,000	Inactive
PORTOLA IMPROVEMENT ASSOCIATION MWC	LA HONDA	90	Active
PUENTE HOUSING SOLUTIONS	PESCADERO	28	Active
REDWOOD GLEN CAMP & CONFERENCE CTR	LOMA MAR	114	Active
REDWOOD TERRACE MUTUAL	LA HONDA	56	Active
SILVA WHOLESALE FLORIST	HALF MOON BAY	30	Inactive
SKYLINE COUNTY WATER DISTRICT	Woodside	1,650	Inactive
SKYLONDA MUTUAL	WOODSIDE	420	Inactive
SPRING CREEK LANE M W C	REDWOOD CITY	40	Inactive
ST JOHN MUTUAL WATER COMPANY	HALF MOON BAY	60	Inactive
ST PATRICKS SEMINARY	MENLO PARK	100	Inactive
STONE PINE MUTUAL WATER COMPANY	HALF MOON BAY	25	Inactive
SYNANON HOME PLACE RANCH	MARSHALL	173	Inactive
TOWN OF HILLSBOROUGH	HILLSBOROUGH	11,766	Active
WESTBOROUGH WATER DISTRICT	SOUTH SAN FRANCISCO	13,486	Active
WOODSIDE MUTUAL	San Jose	195	Inactive