Drinking water quality · 2026
· Verified
What's in City of Antioch, CA tap water
40 contaminants were measured in the City of Antioch, CA water system's 2026 annual report. Each is shown below against its federal limit.
- Reporting year
- 2026
- Contaminants measured
- 40
- Over federal limit
- 0
- Approaching the limit
- 0
- Service area
- CA
Where your water comes from · EPA SDWIS
City of Antioch, CA's drinking water comes from surface water, drawn from 2 sources.
Source
- ANTIOCH MUNICIPAL RESERVOIR
- SAN JOAQUIN RIVER INTAKE
Treatment
- ANTIOCH WTP
Distribution
Also buys water from CONTRA COSTA WATER DISTRICT, RANDALL-BOLD WATER TREATMENT PLANT, and 2 more.
Historical readings · EPA Six-Year Review (2012–2019)
1 contaminant historically over EPA limits in City of Antioch, CA
Every U.S. public water system reports compliance-monitoring data to EPA. The Six-Year Review releases the 2012–2019 window as a single dataset — here's what your system reported, year by year. Values shown are the highest detection per analyte per year, compared to the federal MCL.
| Contaminant | Worst detection | EPA limit | Years (2012–2019) |
|---|---|---|---|
BROMATE worst: 2014 | 0.01 mg/L 1.0× | 0.01 mg/L | '13'14'17 |
TTHM worst: 2018 | 0.074 mg/L 93% | 0.08 mg/L | '12'13'14'16'17'18'19 |
DICHLOROMETHANE worst: 2017 | 0.0034 mg/L within | 0.005 mg/L | '17 |
ARSENIC worst: 2013 | 0.0047 mg/L within below national p90 | 0.01 mg/L | '12'13'14'15'16'17'18'19 |
CADMIUM worst: 2017 | 0.0016 mg/L within near national p90 | 0.005 mg/L | '17 |
FLUORIDE worst: 2012 | 0.95 mg/L within | 4 mg/L | '12'13'14'15'16'17'18'19 |
HAA5 worst: 2017 | 0.0088 mg/L within | 0.06 mg/L | '12'13'14'16'17 |
NITRATE worst: 2013 | 0.994 mg/L within | 10 mg/L | '12'13'14'15'16'17'18'19 |
BARIUM worst: 2012 | 0.16 mg/L within near national p90 | 2 mg/L | '12'16'17'18'19 |
NITRATE NITRITE worst: 2017 | 0.72 mg/L within | 10 mg/L | '16'17'18'19 |
DEHP worst: 2019 | 0.00028 mg/L within | 0.006 mg/L | '19 |
CYANIDE worst: 2018 | 0.0011 mg/L within below national p90 | 0.2 mg/L | '18'19 |
DEHA worst: 2019 | 0.00021 mg/L within | 0.4 mg/L | '19 |
COPPER worst: 2019 | 0.32 mg/L below national p90 | — | '19 |
LEAD worst: 2019 | 0.0028 mg/L | — | '19 |
DBAA worst: 2012 | 0.0029 mg/L | — | '12'13'14'16'17 |
DCAA worst: 2012 | 0.0026 mg/L | — | '12'13'14'16'17 |
MBAA worst: 2016 | 0.0026 mg/L | — | '16 |
TCAA worst: 2017 | 0.0042 mg/L | — | '17 |
BROMODICHLOROMETHANE worst: 2012 | 0.0053 mg/L | — | '12'13'14'16'17'18'19 |
BROMOFORM worst: 2012 | 0.0076 mg/L | — | '12'13'14'16'17'18'19 |
CHLOROFORM worst: 2012 | 0.0029 mg/L | — | '12'13'14'16'17'18'19 |
DIBROMOCHLOROMETHANE worst: 2012 | 0.0079 mg/L | — | '12'13'14'16'17'18'19 |
Physical & aggregate
| Contaminant | Measured | Federal limit | Status |
|---|---|---|---|
| Specific ConductanceA measure of how well water conducts electricity, which tracks dissolved mineral content. | 450 UMHO/CMAverageEntry point | 1600 UMHO/CMMCL | Within the limit |
| AlkalinityA measure of the water's capacity to neutralize acids. | 48.800000000000004 MG/LAverageEntry point | None set | Detected — no federal limit |
| HardnessA measure of dissolved calcium and magnesium minerals. | 78 MG/LAverageEntry point | None set | Detected — no federal limit |
Inorganic chemicals
Other
| Contaminant | Measured | Federal limit | Status |
|---|---|---|---|
| Mcaa | Not detected UG/LHighest single sampleDistribution | None set | None detected |
PFAS ("forever chemicals")
| Contaminant | Measured | Federal limit | Status |
|---|---|---|---|
| 11-Chloroeicosafluoro-3-oxaundecane-1-sulfonic acid (11Cl-PF3OUdS)11-chloroeicosafluoro-3-oxaundecane-1-sulfonic acid, a chlorinated PFAS compound. | Not detected NG/LHighest single sampleEntry point | None set | None detected |
| 4,8-Dioxa-3H-perfluorononanoic acid (ADONA)ADONA, a newer-generation PFAS replacement compound. | Not detected NG/LHighest single sampleEntry point | None set | None detected |
| 4:2 Fluorotelomer sulfonic acid (4:2 FTS)4:2 fluorotelomer sulfonic acid, a PFAS-related compound. | Not detected NG/LHighest single sampleSource water | None set | None detected |
| 6:2 Fluorotelomer sulfonic acid (6:2 FTS)6:2 fluorotelomer sulfonic acid, a PFAS-related compound. | Not detected NG/LHighest single sampleEntry point | None set | None detected |
| 8:2 Fluorotelomer sulfonic acid (8:2 FTS)8:2 fluorotelomer sulfonic acid, a PFAS-related compound. | Not detected NG/LHighest single sampleSource water | None set | None detected |
| 9-Chlorohexadecafluoro-3-oxanonane-1-sulfonic acid (9Cl-PF3ONS)9-chlorohexadecafluoro-3-oxanonane-1-sulfonic acid, a chlorinated PFAS compound. | Not detected NG/LHighest single sampleEntry point | None set | None detected |
| Hexafluoropropylene oxide dimer acidHFPO-DA ('GenX chemicals'), a newer-generation PFAS replacement compound. | Not detected NG/LHighest single sampleSource water | None set | None detected |
| Perfluoro-3-methoxypropanoic acid (PFMPA)Perfluoro-3-methoxypropanoic acid, a PFAS-related compound. | Not detected NG/LHighest single sampleSource water | None set | None detected |
| Perfluoro-4-methoxybutanoic acid (PFMBA)Perfluoro-4-methoxybutanoic acid, a PFAS-related compound. | Not detected NG/LHighest single sampleEntry point | None set | None detected |
| Perfluoro(2-ethoxyethane)sulfonic acid (PFEESA)Perfluoro(2-ethoxyethane)sulfonic acid, a PFAS-related compound. | Not detected NG/LHighest single sampleSource water | None set | None detected |
| Perfluorodecanoic acid (PFDA)Perfluorodecanoic acid, a longer-chain PFAS 'forever chemical.' | Not detected NG/LHighest single sampleEntry point | None set | None detected |
| Perfluorododecanoic acid (PFDoA)Perfluorododecanoic acid, a longer-chain PFAS 'forever chemical.' | Not detected NG/LHighest single sampleEntry point | None set | None detected |
| Perfluoroheptanesulfonic acid (PFHpS)Perfluoroheptanesulfonic acid, a PFAS 'forever chemical.' | Not detected NG/LHighest single sampleEntry point | None set | None detected |
| Perfluoroheptanoic acidPerfluoroheptanoic acid, a PFAS 'forever chemical.' | Not detected NG/LHighest single sampleSource water | None set | None detected |
| Perfluorohexanoic acidPerfluorohexanoic acid, a shorter-chain PFAS 'forever chemical.' | Not detected NG/LHighest single sampleEntry point | None set | None detected |
| Perfluorononanoic acidPerfluorononanoic acid, a PFAS 'forever chemical.' | Not detected NG/LHighest single sampleSource water | None set | None detected |
| Perfluoropentanesulfonic acid (PFPeS)Perfluoropentanesulfonic acid, a PFAS 'forever chemical.' | Not detected NG/LHighest single sampleSource water | None set | None detected |
| Perfluoropentanoic acidPerfluoropentanoic acid, a shorter-chain PFAS 'forever chemical.' | Not detected NG/LHighest single sampleSource water | None set | None detected |
| Perfluoroundecanoic acid (PFUnA)Perfluoroundecanoic acid, a longer-chain PFAS 'forever chemical.' | Not detected NG/LHighest single sampleSource water | None set | None detected |
| PFBAPerfluorobutanoic acid, a shorter-chain PFAS 'forever chemical.' | Not detected NG/LHighest single sampleSource water | None set | None detected |
Metals
| Contaminant | Measured | Federal limit | Status |
|---|---|---|---|
| CalciumA naturally occurring mineral that contributes to water hardness. | 5.666666666666667 MG/LAverageEntry point | None set | Detected — no federal limit |
| MagnesiumA naturally occurring mineral that contributes to water hardness. | 9.9 MG/LAverageEntry point | None set | Detected — no federal limit |
People also ask about City of Antioch, CA's water
+Is City of Antioch, CA tap water safe to drink in 2026?
Every one of the 40 contaminants measured in City of Antioch, CA's 2026 Consumer Confidence Report is below its federal limit. "Safe" under the EPA's drinking-water standards is health-based, not aesthetic — but by those standards, no measured contaminant in this report exceeds its enforceable threshold. Individual health concerns (e.g. immunocompromised, infant, pregnancy) may warrant additional filtering regardless of compliance.
+What contaminants are in City of Antioch, CA tap water?
40 contaminants were measured in City of Antioch, CA's 2026 Consumer Confidence Report, spanning pfas ("forever chemicals"), disinfection byproducts, and other. 7 have an enforceable federal limit; the rest are detected but unregulated. Every measured value, in the utility's own units, is on this page.
+Where does the data on this page come from?
Every value is transcribed from City of Antioch, CA's 2026 Consumer Confidence Report — the annual drinking-water report every U.S. public water utility is required by federal law to publish. The original source document is archived and viewable on this site. A water-quality report covers an entire service area, not a single address.
+How often is City of Antioch, CA's water quality data updated?
Each U.S. public water utility publishes one Consumer Confidence Report per year, covering the prior calendar year's measurements. This page reflects the 2026 report; a new report will replace it once the utility publishes its next annual update.