Water Quality: Chico, CA

30 water systems • 23,374 people served

Multiple Health Violations
639
Total Violations
378
Health-Based Violations
30
Water Systems
23,374
Population Served

Water Quality Summary

Chico is served by 30 public water systems with a combined service population of 23,374 people, and has 639 EPA Safe Drinking Water Act violations on record. Critically, 378 of those are health-based violations, meaning one or more contaminants were detected above EPA-established safe levels — a serious public health concern. Chico's violation count is 1231% above the national average for California. Contaminants associated with violations include Contaminant 1022, E. coli, Fecal Coliform, Gross Alpha, Haloacetic Acids.

Contaminants Found

Contaminant 1022
E. coli

Causes gastrointestinal illness; certain strains (e.g., O157:H7) can cause severe kidney failure and death.

Common source: Fecal contamination from humans or animals entering the water supply

EPA limit: Zero (no E. coli permitted in drinking water)

Fecal Coliform

Indicates direct fecal contamination; associated with diarrhea, cramps, nausea, and potential severe illness.

Common source: Human and animal fecal waste

EPA limit: Zero tolerance (any positive triggers violations)

Gross Alpha

Alpha-emitting radioactive particles increase cancer risk, particularly from bone and other internal cancers.

Common source: Natural uranium and radium in geological formations

EPA limit: 15 pCi/L (excluding radon and uranium)

Haloacetic Acids

Linked to increased cancer risk and potential reproductive and developmental effects with long-term exposure.

Common source: Reaction of chlorine disinfectants with organic matter in treated water

EPA limit: 0.060 mg/L (60 ppb)

Nitrate-Nitrite

Causes methemoglobinemia in infants and may pose cancer risks with long-term exposure.

Common source: Fertilizer runoff, septic systems, animal feedlots, natural deposits

EPA limit: 10 mg/L (as nitrogen)

Selenium

Hair loss, nail brittleness, and nervous system damage at elevated concentrations.

Common source: Natural geological deposits, mining discharges, oil refinery waste

EPA limit: 0.05 mg/L (50 ppb)

Stage 2 DBP

Trihalomethanes and haloacetic acids that increase cancer risk and may cause adverse reproductive outcomes.

Common source: Chlorine disinfection reacting with natural organic matter in source water

EPA limit: TTHM: 0.080 mg/L; HAA5: 0.060 mg/L

Total Haloacetic Acids (HAA5)

Haloacetic acids are associated with increased cancer risk and potential reproductive and developmental effects.

Common source: Reaction of chlorine disinfectants with organic matter in treated water

EPA limit: 0.060 mg/L (60 ppb)

Water Systems Serving Chico

System Name PWSID Source Population Violations
DEL ORO WATER CO.-PARADISE PINES CA0410011 Surface Water 10,940 0
DEL ORO WATER CO-FERNDALE CA1210007 Groundwater 1,662 0
DEL ORO WATER COMPANY - STRAWBERRY DIV. CA5510007 Surface Water 1,295 14
DEL ORO RIVER ISLAND SERV TERR #1 CA5400665 Surface Water 1,280 212
DEL ORO CALIFORNIA PINES DISTRICT CA5410034 Groundwater 944 52
DEL ORO WATER CO.-JOHNSON PARK CA4510015 Groundwater 904 0
DEL ORO WATER CO.-LIME SADDLE MARINA CA0405001 Surface Water 895 0
DEL ORO TRAVER DISTRICT CA5400553 Groundwater 657 10
DEL ORO WATER CO.-STIRLING BLUFFS CA0410018 Surface Water 521 18
GRIDLEY FARM LABOR HOUSING CA0400012 Groundwater 460 7
BUTTE CREEK ESTATES MUTUAL WATER CO CA0400007 Groundwater 399 15
BENBOW-DEL ORO W.C. CA1200671 Surface Water 370 4
DEL ORO WATER CO.-MAGALIA CA0410009 Groundwater 340 13
DEL ORO GRANDVIEW GARDENS DISTRICT CA5400666 Groundwater 323 62
DEL ORO WC - COUNTRY ESTATES DIST CA1500314 Groundwater 297 11
GRAN MUTUAL WATER CO CA0400008 Groundwater 290 1
DEL ORO WC - BLACK BUTTE DISTRICT CA1100404 Groundwater 277 0
ALMOND GROVE MOBILE PARK CA0400040 Groundwater 253 7
DEL ORO WC - ARBUCKLE DISTRICT CA0605011 Groundwater 185 1
DEL ORO WATER CO. - HAT CREEK DISTRICT CA4500022 Surface Water 185 12
KEEFER CREEK ESTATES CA0400151 Groundwater 160 1
SIERRA MOON MUTUAL WATER COMPANY CA0409183 Groundwater 120 91
DEL ORO WC - LARKSPUR MEADOWS CA5200574 Groundwater 116 5
DEL ORO WATER COMPANY - BUZZTAIL DIST. CA0400091 Groundwater 106 13
DEL ORO WATER CO - METROPOLITAN DISTRICT CA1000057 Groundwater 92 18
DEL ORO RIVER ISLAND SERV TERR #2 CA5402048 Groundwater 89 47
BLUE OAK TERRACE MUTUAL CA0409181 Groundwater 81 4
FOREST KNOLLS MUTUAL WATER CO CA0400078 Groundwater 46 8
DEL ORO EAST PLANO DISTRICT CA5400767 Groundwater 46 9
HARTLEY MUTUAL WATER SYSTEM CA0400003 Groundwater 41 4

Concerned About Your Water?

A home water filter can remove common contaminants. NSF-certified filters are tested against EPA standards.

Consider a reverse osmosis system for comprehensive filtration or a carbon filter for basic improvement.

Other Cities in California

Los Angeles 130 violations • 4,029,090 served San Jose 146 violations • 3,387,313 served Oakland 17 violations • 1,444,562 served San Diego 73 violations • 1,422,927 served Sacramento 1022 violations • 1,219,532 served Burlingame 1 violations • 884,627 served Anaheim 15 violations • 789,505 served Perris 0 violations • 666,581 served

View all cities in California →

Data Sources

Drinking water violation data from the EPA Safe Drinking Water Information System (SDWIS). Data includes all recorded violations for active community water systems.

Verify at epa.gov • Search ECHO for CA