Is Chico, CA tap water safe?
Supplied by California Water Service – Chico · serves 110,473 people (30,464 connections) · Groundwater · EPA ID CA0410002
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, PFHxS, the PFAS Hazard Index above the federal limit in EPA's 2023–2025 testing (PFOS 16.8 ppt vs a limit of 4 ppt, PFHxS 16.9 ppt vs a limit of 10 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 2024 – now, still in progress (results reported so far). 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 California Water Service – Chico'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 (408) 367-8490. EPA: how to find it.
PFAS (“forever chemicals”)
EPA UCMR 5: 37 entry points tested Sep 2023 to Jul 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 | 3.4 ppt 85% of the limit |
| PFOS Above limit Limit 4 ppt | 16.8 ppt 4.19× the limit |
| PFHxS Above limit Limit 10 ppt | 16.9 ppt 1.69× 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) Above limit Limit 1 | 1.7 |
| PFBS Detected, below limit Guideline 2,000 ppt | 6.7 ppt |
| PFBA Not detected Guideline 6,000 ppt | – |
| PFHxA Detected, below limit Guideline 3,000 ppt | 3 ppt |
| PFPeA Detected, no limit | 2.65 ppt |
For context: the PFOS average is higher than at 94% of the California systems EPA tested and the PFHxS average is higher than at 98% 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
Detected in 3 of 74 samples. Highest result 11.7 ppb. EPA's non-enforceable screening level is 10 ppb. Below screening level The screening level is how EPA decides what to study further, not a health limit. There is no federal limit for lithium and no filter is certified to remove it. About lithium.
Lead and copper
Latest 90th percentile: 0 ppb lead (Jan 2024 – now (in progress)). Below action level
Highest since 2016: 1.26 ppb (Dec 2020).
| Monitoring period | Lead (90th pct.) |
|---|---|
| Jan 2024 – now (in progress) | 0 ppb |
| Jan 2021 – Dec 2023 | 0 ppb |
| Jan 2018 – Dec 2020 | 1.26 ppb |
Earlier results (9)
| Jan 2015 – Dec 2017 | 0 ppb |
| Jan 2012 – Dec 2014 | 0 ppb |
| Jan 2011 – Dec 2013 | 0 ppb |
| Jan 2008 – Dec 2010 | 0 ppb |
| Jan 2005 – Dec 2007 | 0 ppb |
| Jan 2004 – Dec 2004 | 0 ppb |
| Jan 2002 – Dec 2004 | 0 ppb |
| Jan 2001 – Dec 2003 | 0 ppb |
| Jan 2001 – Dec 2001 | 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
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 | 5.9 ppb | 300 ppb |
| Vanadium | 34 ppb | 21 ppb |
| 1,4-Dioxane | 0.45 ppb | 0.35 ppb |
| Chlorate | 460 ppb | 210 ppb |
| Chromium-6 | 7.3 ppb | – |
| Strontium | 0.37 ppm | 1.5 ppm |
Where it serves
Chico
ZIP codes the system reported serving: 95926, 95928, 95951, 95963, 95973
Nearby utilities
- City of Gridley Gridley · 28 mi · PFAS above limit
- City of Yuba City Yuba City · 44 mi
- City of Wheatland Wheatland · 55 mi · PFAS above limit
- City of Redding Redding · 63 mi · PFAS above limit
- City of Lincoln Lincoln · 67 mi
- City of Roseville Roseville · 73 mi
Questions
Is Chico tap water safe to drink?
Most of Chico gets its water from California Water Service – Chico. California Water Service – Chico 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 Chico water have PFAS?
Yes. EPA's 2023–2025 testing of California Water Service – Chico found 6 PFAS at least once. The highest entry-point averages were above the federal limit for PFOS and PFHxS: PFOS 16.8 ppt, PFHxS 16.9 ppt (limit 4 ppt for PFOA and PFOS, 10 ppt for the others).
What is the lead level in Chico water?
The most recent 90th-percentile lead result for California Water Service – Chico is 0 ppb, for the monitoring period that began Jan 2024 (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 CA0410002: violations, enforcement and inspections, straight from EPA.
- EPA UCMR 5 data: the PFAS and lithium results (search the file for PWSID CA0410002).
- EPA SDWIS download: the lead results, population and violation records we use.
- The utility's annual water quality report (Consumer Confidence Report): ask California Water Service – Chico at (408) 367-8490, 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.