Water Quality Report · Updated October 07, 2026
CAL-WATER SERVICE CO.-CHICO
CAL-WATER SERVICE CO.-CHICO delivers tap water graded C (69/100) by TapWaterSafety.org. The utility serves approximately 114,925 residents in SAN JOSE, California using groundwater. The most significant water quality concerns are: PFAS contamination; Perfluorohexane sulfonate (PFHXS) significantly above health guideline; Haloacetic acids (HAA5) significantly above health guideline; Chromium (hexavalent) significantly above health guideline; Arsenic detected. For questions, the utility can be reached at 408-367-8490.
Is SAN JOSE tap water safe to drink?
CAL-WATER SERVICE CO.-CHICO delivers tap water that earns a grade of C (69/100) from TapWaterSafety.org — an average rating, with several contaminants above health guidelines but generally compliant with US legal limits.
The utility serves 114,925 residents in SAN JOSE, drawing from groundwater.
Public testing data identifies 13 contaminants in this water above EWG's health-based guidelines, including: Perfluorooctane sulfonate (PFOS), Perfluorohexane sulfonate (PFHXS), Haloacetic acids (HAA5), Chromium (hexavalent), Arsenic, Nitrate, Perfluorooctanoic acid (PFOA), Nitrate and nitrite, Bromodichloromethane, Tetrachloroethylene (perchloroethylene), Haloacetic acids (HAA9), Dibromochloromethane, Total trihalomethanes (TTHMs). For most residents, a properly certified home filter at the kitchen tap is the most cost-effective way to reduce exposure to whatever's in your water. See our filter recommendations below, matched specifically to this utility's contaminant profile.
EPA compliance record
Official U.S. EPA records for CAL-WATER SERVICE CO.-CHICO (system ID CA0410002) for the last 3 years. Checked 2026-10-07.
Source: U.S. EPA Enforcement and Compliance History Online (ECHO), from the Safe Drinking Water Information System. See EPA's full report.
Quick actions for SAN JOSE residents
Top concerns in this water
Based on the most recent EPA and EWG data, these are the most significant water quality issues for CAL-WATER SERVICE CO.-CHICO.
PFAS contamination
Severe concernPerfluorooctane sulfonate (PFOS), Perfluorooctanoic acid (PFOA) detected. PFAS are persistent chemicals linked to cancer and immune effects with no known safe exposure threshold.
Perfluorohexane sulfonate (PFHXS) significantly above health guideline
Moderate concernPerfluorohexane sulfonate (PFHXS) detected at 4.26 ppt, 4255x above the EWG health guideline of 0.001 ppt.
Haloacetic acids (HAA5) significantly above health guideline
Moderate concernHaloacetic acids (HAA5) detected at 34.8 ppb, 348x above the EWG health guideline of 0.1 ppb.
Chromium (hexavalent) significantly above health guideline
Moderate concernChromium (hexavalent) detected at 2.29 ppb, 114x above the EWG health guideline of 0.02 ppb.
Arsenic detected
Moderate concernArsenic detected at 0.136 ppb.
Contact CAL-WATER SERVICE CO.-CHICO
Reach the utility directly for service issues, water quality concerns, or to request your Consumer Confidence Report.
General Contact
Treatment Plant
Recommended water filters for SAN JOSE
Filters matched to the specific contaminants in this water supply.
Filter certified for PFOA/PFOS (NSF/ANSI 53 or 58)
$180-$750Reverse osmosis and some carbon block filters reduce PFAS. Look for certification to NSF/ANSI 53 or 58 for PFOA/PFOS.
Carbon filter certified for VOCs (NSF/ANSI 53)
$180-$599Activated carbon is effective for disinfection byproducts. Look for NSF/ANSI 53 VOC reduction.
Reverse osmosis certified for arsenic (NSF/ANSI 58)
$429-$599Reverse osmosis certified under NSF/ANSI 58 for arsenic is the most reliable home option.
Disclosure: TapWaterSafety earns a commission from purchases made through these links. This does not influence our scoring methodology or filter selection.
Score breakdown
This utility's overall score of 69/100 breaks down across five weighted components. Read the full methodology →
Contaminants detected — international standards comparison
Every contaminant detected, compared side-by-side against US EPA legal limits, the EU Drinking Water Directive (2020/2184), WHO Guidelines, and California's Public Health Goal (the strictest US benchmark). Why we show multiple standards →
| Contaminant | Detected | EWG US health-based |
EPA US legal |
EU DWD Europe |
WHO global |
CA PHG strictest US |
Tested sample year |
Status |
|---|---|---|---|---|---|---|---|---|
| Perfluorooctane sulfonate (PFOS) PFAS |
4.48 ppt | 0.3 | 4.0 | 100 | 100 | 1 | — | EPA violation |
| Perfluorohexane sulfonate (PFHXS) PFAS |
4.26 ppt | 0.001 | 10.0 | — | — | — | — | 4255× over |
| Haloacetic acids (HAA5) Disinfection byproduct |
34.8 ppb | 0.1 | 60.0 | 60 | — | — | — | 348× over |
| Chromium (hexavalent) Heavy metal |
2.29 ppb | 0.02 | — | — | — | — | — | 114× over |
| Arsenic Heavy metal |
0.136 ppb | 0.004 | 10.0 | 10 | 10 | 0.004 | — | 34× over |
| Nitrate Inorganic |
2.11 ppm | 0.14 | 10.0 | 11.3 | 11.3 | 10 | — | 15× over |
| Perfluorooctanoic acid (PFOA) PFAS |
1.22 ppt | 0.09 | 4.0 | 100 | 100 | 0.007 | — | 14× over |
| Nitrate and nitrite Inorganic |
1.49 ppm | 0.14 | 10.0 | 11.3 | 11.3 | 10 | — | 11× over |
| Bromodichloromethane Disinfection byproduct |
0.172 ppb | 0.06 | — | — | — | — | — | 2.9× over |
| Tetrachloroethylene (perchloroethylene) Volatile organic compound |
0.155 ppb | 0.06 | 5.0 | — | — | — | — | 2.6× over |
| Haloacetic acids (HAA9) Disinfection byproduct |
0.136 ppb | 0.06 | — | — | — | — | — | 2.3× over |
| Dibromochloromethane Disinfection byproduct |
0.152 ppb | 0.1 | — | — | — | — | — | 1.5× over |
| Total trihalomethanes (TTHMs) Disinfection byproduct |
0.226 ppb | 0.15 | 80.0 | 100 | — | — | — | 1.5× over |
| Vanadium Other |
17.8 ppb | 21.0 | — | — | — | — | — | Below guideline |
| Dibromoacetic acid Disinfection byproduct |
0.0214 ppb | 0.03 | — | — | — | — | — | Below guideline |
| Chloroform Disinfection byproduct |
0.205 ppb | 0.4 | — | — | — | — | — | Below guideline |
| Chlorate Disinfection byproduct |
77.9 ppb | 210.0 | — | — | — | — | — | Below guideline |
| Trichloroacetic acid Disinfection byproduct |
0.0214 ppb | 0.1 | — | — | — | — | — | Below guideline |
| Uranium Radiological |
0.07 pCi/L | 0.43 | 20.0 | 30 | 30 | 0.43 | — | Below guideline |
| Dichloroacetic acid Disinfection byproduct |
0.0257 ppb | 0.2 | — | — | — | — | — | Below guideline |
| Perfluoropentane sulfonic acid (PFPeS) PFAS |
0.063 ppt | 1.0 | — | — | — | — | — | Below guideline |
| Bromoform Disinfection byproduct |
0.0293 ppb | 0.5 | — | — | — | — | — | Below guideline |
| 1,4-Dioxane Semi-volatile organic compound |
0.0179 ppb | 0.35 | — | — | 50 | 1 | — | Below guideline |
| Strontium Radiological |
45.9 ppb | 1500.0 | — | — | — | — | — | Below guideline |
| Manganese Heavy metal |
0.308 ppb | 100.0 | — | 50 | 80 | — | — | Below guideline |
| Perfluorohexanoic Acid (PFHxA) PFAS |
0.561 ppt | 1000.0 | — | — | — | — | — | Below guideline |
| 1,1-Dichloroethane Volatile organic compound |
0.00139 ppb | 3.0 | — | — | — | — | — | Below guideline |
| Perfluorobutane sulfonate (PFBS) PFAS |
0.872 ppt | 2000.0 | — | — | — | — | — | Below guideline |
| Perfluoropentanoic Acid (PFPeA) PFAS |
0.436 ppt | 1000.0 | — | — | — | — | — | Below guideline |
| Perfluoroheptanoic acid (PFHPA) PFAS |
0.142 ppt | 1000.0 | — | — | — | — | — | Below guideline |
| Perfluorobutanoic Acid (PFBA) PFAS |
0.088 ppt | 1000.0 | — | — | — | — | — | Below guideline |
| 4-Androstene-3,17-dione Other |
0.005 ppt | — | — | — | — | — | — | Below guideline |
| Chlorodifluoromethane Other |
0.0396 ppb | — | — | — | — | — | — | Below guideline |
| Chromium (total) Heavy metal |
0.748 ppb | — | 100.0 | — | — | — | — | Below guideline |
| cis-1,2-Dichloroethylene Volatile organic compound |
0.145 ppb | — | 70.0 | — | — | — | — | Below guideline |
| Lithium Other |
0.391 ppb | — | — | — | — | — | — | Below guideline |
All values in the unit of the detected level. Red cells indicate the detected level exceeds that standard. Some contaminants have limits in some jurisdictions but not others (shown as —). The "Tested" column shows the year each contaminant sample was collected.
Sources: US EPA, EU Drinking Water Directive 2020/2184, WHO Guidelines (4th ed.), California OEHHA PHGs, EWG Tap Water Database.
CAL-WATER SERVICE CO.-CHICO service area
This water system serves 1 community in Butte County, California. Click any city for its dedicated tap water quality page.
Find the right filter for SAN JOSE water
Browse filter categories by water-quality concern. Each option below is NSF-certified for the matched contaminant type.