Modesto, CA water quality
Modesto, CA is served by 62 public water systems, serving 255,008 people combined. Across those systems, we count 81 health-based violations in the last 5 years. The worst Tap Grade among them is C.
Water systems serving Modesto
MODESTO, CITY OF
MODESTO, CA · 218,771 served
CITY OF MODESTO - SALIDA
MODESTO, CA · 14,537 served
CITY OF WATERFORD
WATERFORD, CA · 8,788 served
GREGORI HIGH SCHOOL
MODESTO, CA · 2,000 served
CITY OF MODESTO - DEL RIO
MODESTO, CA · 1,327 served
CITY OF MODESTO - SOUTH TURLOCK
MODESTO, CA · 1,099 served
CITY OF MODESTO - GRAYSON
MODESTO, CA · 914 served
HILLSVIEW HOMES
MODESTO, CA · 887 served
HART- RANSOM UNION SCHOOL & DISTRICT
MODESTO, CA · 650 served
RIVERDALE PARK TRACT CSD
MODESTO, CA · 610 served
WATERFORD - HICKMAN
WATERFORD, CA · 597 served
WOODWARD RESERVOIR WATER SYSTEM
MODESTO, CA · 537 served
STANISLAUS UNION SCHOOL DIST
MODESTO, CA · 390 served
5033 PENTECOST
MODESTO, CA · 302 served
NMIP FIRE & WATER SYSTEM, LLC
MODESTO, CA · 300 served
COVENANT GROVE CHURCH
MODESTO, CA · 300 served
RAM NAAM MANDALI CHURCH OF MODESTO
MODESTO, CA · 250 served
PARK HEIGHTS MUTUAL WATER CO
MODESTO, CA · 250 served
PARADISE SCHOOL
MODESTO, CA · 218 served
CITY OF MODESTO - WALNUT MANOR
MODESTO, CA · 175 served
CITY OF MODESTO - NORTH TURLOCK
MODESTO, CA · 172 served
STRATOS WAY WATER COMPANY, INC
MODESTO, CA · 135 served
GROVER LANDSCAPE WATER SYSTEM
MODESTO, CA · 125 served
KIERNAN BUSINESS CENTER
MODESTO, CA · 120 served
CITY OF MODESTO - CENTRAL TURLOCK
MODESTO, CA · 119 served
THE FRUIT YARD RESTAURANT
MODESTO, CA · 118 served
SHILOH SCHOOL DISTRICT
MODESTO, CA · 105 served
RATTO BROS, INC
MODESTO, CA · 100 served
WOOD COLONY CHRISTIAN SCHOOL
MODESTO, CA · 90 served
MORNINGSIDE MOBILEHOME PARK
MODESTO, CA · 67 served
LIBERTY BAPTIST CHURCH
MODESTO, CA · 65 served
COUNTRY WESTERN MHRV
MODESTO, CA · 55 served
BRETHREN HERITAGE SCHOOL, INC
MODESTO, CA · 50 served
ROLLING HILLS NUT COMPANY
HICKMAN, CA · 45 served
STORER TRANSPORTATION
MODESTO, CA · 40 served
STERLING INDUSTRIAL
MODESTO, CA · 35 served
JENNINGS WWTP
MODESTO, CA · 30 served
MCHENRY BUSINESS PARK
MODESTO, CA · 27 served
SMART STOP FOOD MART (EH)
MODESTO, CA · 26 served
JOE'S FOOD MART WATER SYSTEM
MODESTO, CA · 26 served
BASSO BRIDGE FISHING/BOATING ACCESS
MODESTO, CA · 26 served
5801 MCHENRY AVE
MODESTO, CA · 26 served
4937 BECKWITH WATER SYSTEM
MODESTO, CA · 26 served
FRANK RAINES PARK OHV
MODESTO, CA · 26 served
LA GRANGE PARK-OHV
MODESTO, CA · 26 served
FOX GROVE FISHING ACCESS
MODESTO, CA · 26 served
SHILOH-PARADISE BASEBALL FOR YOUTH
MODESTO, CA · 26 served
RIVER ROAD MUTUAL WATER COMPANY
MODESTO, CA · 26 served
ZANSCO
MODESTO, CA · 25 served
LOS INDIOS WATER SYSTEM
MODESTO, CA · 25 served
MODESTO RESERVOIR
MODESTO, CA · 25 served
FEE WATER SYSTEM
MODESTO, CA · 25 served
WEST COAST SAND & GRAVEL
MODESTO, CA · 25 served
ELKS LODGE 1282
MODESTO, CA · 25 served
BEL PASSI BASEBALL
MODESTO, CA · 25 served
MODESTO CHRISTIAN CENTER (WATERSYSTEM)
MODESTO, CA · 25 served
WATERFORD SPORTSMEN'S CLUB
MODESTO, CA · 25 served
NINO'S PLACE WATER SYSTEM
MODESTO, CA · 25 served
PENTECOST PROPERTIES WATER SYSTEM
MODESTO, CA · 25 served
CHARITY WAY WATER SYSTEM
MODESTO, CA · 25 served
FISHER NUT
MODESTO, CA · 25 served
MODESTO IRRIGATION DISTRICT
MODESTO, CA · 23 served
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Is Modesto, CA tap water safe to drink?
62 public water systems serve Modesto, CA, with 81 health-based violations in the last 5 years across them. The worst Tap Grade among them is C. A Tap Grade summarizes public EPA compliance records; it is not a determination that water is safe or unsafe to drink.
Does Modesto's water have lead in it?
The most recent 90th-percentile lead sample is 12 ppb, versus the EPA action level of 15 ppb.
Has PFAS been detected in Modesto's water?
Yes — at least one water system serving Modesto has detected PFAS under UCMR5.
Other cities in California
See all of California →Source: EPA SDWIS/ECHO · Data as of 2026Q2
TapGraded presents public EPA data for information only — it is not health advice and not a determination that any water is safe or unsafe to drink. For health concerns, contact your water utility or local health department.