City of Stockton water quality
Stockton, CA · serves 192,702 people (52,125 connections) · Surface water · Local government · EPA ID CA3910012
Data: U.S. EPA · How we read the data · How we check it
Buys water from Stockton East Water District. Treated water bought from another system can carry that system's contaminants.
Summary
PFAS above the 2024 federal limits. Systems have until 2029 to meet the PFAS limits.
Is it an emergency? No: PFAS limits are about years of exposure, not a glass of water, and nothing in EPA's data calls for you to stop drinking the water today. If your utility ever issues a boil-water or do-not-drink notice, follow it.
- PFAS
- Above limitPFOS above the federal limit in EPA's 2023–2025 testing (PFOS 14 ppt vs a limit of 4 ppt, where ppt = parts per trillion).
- Lead
- Below action level0 ppb (parts per billion) at the 90th percentile: 9 in 10 homes sampled were at or below it. Action level 15 ppb, falling to 10 ppb in Nov 2027. Monitoring period Jan 2025 – now, still in progress (results reported so far). Your home's pipes can make yours higher.
- Violations
- Resolved3 health-based violations since 2016, most recently Apr 2023.
- Pregnant, or mixing baby formula with tap water? Babies drink more water for their size, so PFAS exposure matters more for them. Consider bottled water or a filter certified for PFAS for formula, and ask your doctor. Health effects.
- To lower your PFAS exposure now, a home filter certified for PFAS reduction works (reverse osmosis, or activated carbon certified to NSF/ANSI 53 or 58). Filters for these results.
- Built before 1986, or not sure what your service line is made of? Check your service line and test your tap. Utility data can't show your pipes.
- Tested your own tap? Compare your result with these numbers. Moving? Compare this system with another.
- Read City of Stockton's annual water quality report (Consumer Confidence Report). It lists every regulated contaminant tested and is usually on the utility's website or mailed with your bill, and you can also request it at (209) 937-8438. EPA: how to find it.
PFAS (“forever chemicals”)
EPA UCMR 5: 17 entry points tested Feb 2023 to Dec 2025. "Average" is the highest entry-point average (non-detects counted as zero), the way EPA compares UCMR 5 results to the limits. ppt = parts per trillion. These results do not determine compliance.
| Contaminant | Highest average |
|---|---|
| PFOA One sample above limit Limit 4 ppt | 3.35 ppt 84% of the limit |
| PFOS Above limit Limit 4 ppt | 14 ppt 3.5× the limit |
| PFHxS Not detected Limit 10 ppt | – |
| PFNA Not detected Limit 10 ppt | – |
| HFPO-DA (GenX) Not detected Limit 10 ppt | – |
| Hazard Index (a combined score for PFHxS, PFNA, GenX and PFBS, where above 1 is over the limit) Detected, below limit Limit 1 | 0.0015 |
| PFBS Detected, below limit Guideline 2,000 ppt | 3.1 ppt |
| PFBA Not detected Guideline 6,000 ppt | – |
| PFHxA Not detected Guideline 3,000 ppt | – |
For context: the PFOS average is higher than at 92% of the California systems EPA tested.
29 PFAS tested, 3 detected at least once. "Not detected" means below EPA's reporting limit (about 2 to 20 ppt depending on the chemical), not proven zero. PFAS not listed were not detected. The limits for PFHxS, PFNA, GenX and the Hazard Index were proposed for rescission in May 2026. That proposal is not final. Systems have until 2029 to meet the limits.
Lithium
Not detected in 38 samples (reporting limit 9 ppb). About lithium.
Lead and copper
Latest 90th percentile: 0 ppb lead (Jan 2025 – now (in progress)). Below action level
| Monitoring period | Lead (90th pct.) |
|---|---|
| Jan 2025 – now (in progress) | 0 ppb |
| Jan 2024 – now (in progress) | 0 ppb |
| Jan 2021 – Dec 2023 | 0 ppb |
Earlier results (9)
| Jan 2018 – Dec 2020 | 0 ppb |
| Jan 2015 – Dec 2017 | 0 ppb |
| Jan 2014 – Dec 2016 | 0 ppb |
| Jan 2010 – Dec 2012 | 0 ppb |
| Jan 2008 – Dec 2010 | 0 ppb |
| Jan 2007 – Dec 2007 | 0 ppb |
| Jan 2006 – Dec 2006 | 4.1 ppb |
| Jan 2004 – Dec 2004 | 5 ppb |
| Jan 2001 – Dec 2003 | 0 ppb |
Lead comes from pipes and fixtures, not the source water, so it varies home to home. The 90th percentile means 9 in 10 sampled homes were at or below it. More on lead.
Violations
| When | What happened |
|---|---|
| Jan 2023 – Apr 2023 2 times | The running annual average for TTHM was above the legal limit. EPA record: TTHM · Maximum Contaminant Level Violation, Average · measured 0.083 mg/l (limit 0.080 mg/L) Resolved |
| Mar 2016 | A required step to remove or kill germs (filtration, disinfection or fixing a contaminated well) was not done properly. EPA record: Surface Water Treatment Rule · Treatment Technique (SWTR and GWR) (limit ) Resolved |
Health-based violations mean a contaminant exceeded a limit or a required treatment step was missed. Monitoring and reporting violations mean required tests or reports were late or missing, so the water's quality during that time is unknown. The total includes every violation in EPA's records, most of them paperwork.
Earlier EPA testing (2013–2020)
| Contaminant | Highest | Guideline |
|---|---|---|
| Manganese | 77 ppb | 300 ppb |
| 1,4-Dioxane | 0.21 ppb | 0.35 ppb |
| Vanadium | 33 ppb | 21 ppb |
| Chlorate | 440 ppb | 210 ppb |
| Molybdenum | 1.6 ppb | 40 ppb |
| Strontium | 0.79 ppm | 1.5 ppm |
| Chromium-6 | 6.6 ppb | – |
Where it serves
ZIP codes the system reported serving: 95205, 95206, 95207, 95209, 95210, 95212, 95215, 95219, 95231
Nearby utilities
- California Water Service – Stockton Stockton · same area
- City of Lodi Lodi · 10 mi · PFAS above limit
- City of Lathrop Lathrop · 12 mi · PFAS above limit
- San Joaquin County – Mokelumne Acres Woodbridge · 14 mi · PFAS above limit
- City of Manteca Manteca · 14 mi · PFAS above limit
- City of Tracy Tracy · 19 mi
Questions
Is City of Stockton water safe to drink?
City of Stockton had 3 health-based violations since 2016, all since resolved. EPA testing found PFAS above the 2024 federal limits, which systems must meet by 2029. Federal data can't tell you about your own pipes: lead comes from service lines and plumbing, so test your tap if your home was built before 1986. For the official word, read the utility's annual Consumer Confidence Report.
Does City of Stockton water have PFAS?
Yes. EPA's 2023–2025 testing of City of Stockton found 3 PFAS at least once. The highest entry-point averages were above the federal limit for PFOS: PFOS 14 ppt (limit 4 ppt for PFOA and PFOS, 10 ppt for the others).
What is the lead level in City of Stockton water?
The most recent 90th-percentile lead result for City of Stockton is 0 ppb, for the monitoring period that began Jan 2025 (still in progress). The federal action level is 15 ppb, falling to 10 ppb in November 2027. The 90th percentile means 9 in 10 homes sampled were at or below this number. Individual homes can be higher.
Check these numbers yourself
Every figure on this page comes from public EPA records. You don't have to take our word for it:
- EPA's own report for CA3910012: violations, enforcement and inspections, straight from EPA.
- EPA UCMR 5 data: the PFAS and lithium results (search the file for PWSID CA3910012).
- EPA SDWIS download: the lead results, population and violation records we use.
- The utility's annual water quality report (Consumer Confidence Report): ask City of Stockton at (209) 937-8438, or see EPA's guide to finding it.
Found something that doesn't match? Tell us and we'll check it against EPA's records. How we check our data.
Source: U.S. EPA drinking water records and PFAS testing (UCMR 5). How we read the data.