San Joaquin County – Mokelumne Acres water quality
Woodbridge, CA · serves 3,802 people (1,151 connections) · Groundwater · Local government · EPA ID CA3910017
Data: U.S. EPA · How we read the data · How we check it
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 limitPFOA, PFOS above the federal limit in EPA's 2023–2025 testing (PFOA 8.1 ppt vs a limit of 4 ppt, PFOS 12.8 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 ending Dec 2024. Your home's pipes can make yours higher.
- Violations
- None health-basedNo health-based violations since 2016.
- 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 San Joaquin County – Mokelumne Acres'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) 468-3090. EPA: how to find it.
PFAS (“forever chemicals”)
EPA UCMR 5: 5 entry points tested Jan 2025 to Jul 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 Above limit Limit 4 ppt | 8.1 ppt 2.02× the limit |
| PFOS Above limit Limit 4 ppt | 12.8 ppt 3.2× the limit |
| PFHxS Detected, below limit Limit 10 ppt | 4.5 ppt 45% of the limit |
| 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 | 0.45 |
| PFBS Detected, below limit Guideline 2,000 ppt | 8 ppt |
| PFBA Not detected Guideline 6,000 ppt | – |
| PFHxA Detected, below limit Guideline 3,000 ppt | 3.45 ppt |
| PFPeA Detected, no limit | 3.25 ppt |
For context: the PFOA average is higher than at 94% of the California systems EPA tested and the PFOS average is higher than at 92% of the California systems EPA tested.
29 PFAS tested, 6 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 10 samples (reporting limit 9 ppb). About lithium.
Lead and copper
Latest 90th percentile: 0 ppb lead (Jan 2022 – Dec 2024). Below action level
Highest since 2016: 1.9 ppb (Dec 2018).
| Monitoring period | Lead (90th pct.) |
|---|---|
| Jan 2022 – Dec 2024 | 0 ppb |
| Jan 2019 – Dec 2021 | 0 ppb |
| Jan 2016 – Dec 2018 | 1.9 ppb |
Earlier results (9)
| Jan 2013 – Dec 2015 | 1.7 ppb |
| Jan 2010 – Dec 2012 | 0 ppb |
| Jan 2009 – Dec 2009 | 1.9 ppb |
| Jan 2006 – Dec 2006 | 3.5 ppb |
| Jan 2003 – Dec 2005 | 1 ppb |
| Jan 2003 – Dec 2003 | 5 ppb |
| Jan 2000 – Dec 2002 | 0 ppb |
| Jan 2001 – Dec 2001 | 1.3 ppb |
| Jan 2000 – Dec 2000 | 7 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
No violations on record in EPA's Safe Drinking Water Information System.
Where it serves
Woodbridge
ZIP codes the system reported serving: 95258
Nearby utilities
- City of Lodi Lodi · 4 mi · PFAS above limit
- California Water Service – Stockton Stockton · 14 mi
- City of Stockton Stockton · 14 mi · PFAS above limit
- California American Water – Parkway Elk Grove · 17 mi · PFAS above limit
- SCWA – Laguna/Vineyard Vineyard · 21 mi · PFAS above limit
- Florin County Water District Florin · 22 mi · PFAS above limit
Questions
Is San Joaquin County – Mokelumne Acres water safe to drink?
San Joaquin County – Mokelumne Acres has no health-based violations since 2016. 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 San Joaquin County – Mokelumne Acres water have PFAS?
Yes. EPA's 2023–2025 testing of San Joaquin County – Mokelumne Acres found 6 PFAS at least once. The highest entry-point averages were above the federal limit for PFOA and PFOS: PFOA 8.1 ppt, PFOS 12.8 ppt (limit 4 ppt for PFOA and PFOS, 10 ppt for the others).
What is the lead level in San Joaquin County – Mokelumne Acres water?
The most recent 90th-percentile lead result for San Joaquin County – Mokelumne Acres is 0 ppb, for the period ending Dec 2024. 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 CA3910017: violations, enforcement and inspections, straight from EPA.
- EPA UCMR 5 data: the PFAS and lithium results (search the file for PWSID CA3910017).
- EPA SDWIS download: the lead results, population and violation records we use.
- The utility's annual water quality report (Consumer Confidence Report): ask San Joaquin County – Mokelumne Acres at (209) 468-3090, 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.