Rincon Northern Water System water quality
Valley Center, CA · serves 7,003 people (183 connections) · Groundwater · Native American · EPA ID 090600147
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 limitPFOS above the federal limit in EPA's 2023–2025 testing (PFOS 4.45 ppt vs a limit of 4 ppt, where ppt = parts per trillion).
- Lead
- Below action level5 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 Jun 2026. 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 Rincon Northern Water System'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 (760) 749-1051. EPA: how to find it.
PFAS (“forever chemicals”)
EPA UCMR 5: 3 entry points tested Feb 2024 to Nov 2024. "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 | 2.8 ppt 70% of the limit |
| PFOS Above limit Limit 4 ppt | 4.45 ppt 1.11× 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 | 0.00085 |
| PFBS Detected, below limit Guideline 2,000 ppt | 1.7 ppt |
| PFBA Not detected Guideline 6,000 ppt | – |
| PFHxA Detected, below limit Guideline 3,000 ppt | 2.95 ppt |
| PFPeA Detected, no limit | 2.5 ppt |
For context: the PFOS average is higher than at 83% of the California systems EPA tested.
29 PFAS tested, 5 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 6 samples (reporting limit 9 ppb). About lithium.
Lead and copper
Latest 90th percentile: 5 ppb lead (Jan 2026 – Jun 2026). Below action level
Highest since 2016: 107 ppb (Dec 2019).
| Monitoring period | Lead (90th pct.) |
|---|---|
| Jan 2026 – Jun 2026 | < 5 ppb |
| Jul 2025 – Dec 2025 | 5 ppb |
| Jan 2025 – Jun 2025 | < 5 ppb |
Earlier results (9)
| Jul 2024 – Dec 2024 | < 5 ppb |
| Jan 2024 – Jun 2024 | 5 ppb |
| Jul 2023 – Dec 2023 | < 5 ppb |
| Jan 2023 – Jun 2023 | < 5 ppb |
| Jul 2022 – Dec 2022 | 5 ppb |
| Jan 2022 – Jun 2022 | 5 ppb |
| Jul 2021 – Dec 2021 | 5 ppb |
| Jan 2021 – Jun 2021 | < 5 ppb |
| Jul 2020 – Dec 2020 | < 5 ppb |
Copper 90th percentile: 2.32 ppm (Jun 2018), action level 1,300 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
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.
Where it serves
Valley Center
ZIP codes the system reported serving: 92082
Nearby utilities
- City of Escondido Escondido · 8 mi
- Vallecitos Water District San Marcos · 11 mi
- Vista Irrigation District Vista · 13 mi
- City of Oceanside Oceanside · 17 mi
- Carlsbad Municipal Water District Carlsbad · 17 mi
- Olivenhain Municipal Water District Encinitas · 19 mi
Questions
Is Rincon Northern Water System water safe to drink?
Rincon Northern Water System 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 Rincon Northern Water System water have PFAS?
Yes. EPA's 2023–2025 testing of Rincon Northern Water System found 5 PFAS at least once. The highest entry-point averages were above the federal limit for PFOS: PFOS 4.45 ppt (limit 4 ppt for PFOA and PFOS, 10 ppt for the others).
What is the lead level in Rincon Northern Water System water?
The most recent 90th-percentile lead result for Rincon Northern Water System is 5 ppb, for the period ending Jun 2026. 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 090600147: violations, enforcement and inspections, straight from EPA.
- EPA UCMR 5 data: the PFAS and lithium results (search the file for PWSID 090600147).
- EPA SDWIS download: the lead results, population and violation records we use.
- The utility's annual water quality report (Consumer Confidence Report): ask Rincon Northern Water System at (760) 749-1051, 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.