Stillwater Utilities Authority water quality
Stillwater, OK · serves 53,000 people (17,348 connections) · Surface water · Local government · EPA ID OK1021220
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 6.13 ppt vs a limit of 4 ppt, where ppt = parts per trillion).
- Lithium
- Above screening levelHighest result 21.6 ppb. EPA uses 10 ppb to decide what to study further. It is not a health limit, and there is no federal limit for lithium. About 1 in 4 systems tested were above it.
- Lead
- Below action level2.6 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 2026 – now, still in progress (results reported so far). Your home's pipes can make yours higher.
- Violations
- Resolved16 health-based violations since 2016, most recently Feb 2023. 6 required an urgent public notice within 24 hours (the kind behind boil-water notices), most recently Oct 2018. What to do if you get a notice.
- 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.
- Got a boil-water or do-not-drink notice? What each notice means and what to do.
- Tested your own tap? Compare your result with these numbers. Moving? Compare this system with another.
- Read Stillwater Utilities Authority'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 (405) 533-8452. EPA: how to find it.
PFAS (“forever chemicals”)
EPA UCMR 5: 1 entry point tested Dec 2023 to Sep 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 Not detected Limit 4 ppt | – |
| PFOS Above limit Limit 4 ppt | 6.13 ppt 1.53× the limit |
| PFHxS Detected, below limit Limit 10 ppt | 4.58 ppt 46% 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 | 0.46 |
| PFBS Detected, below limit Guideline 2,000 ppt | 0.75 ppt |
| PFBA Not detected Guideline 6,000 ppt | – |
| PFHxA Detected, below limit Guideline 3,000 ppt | 2.82 ppt |
| PFPeA Detected, no limit | 1.9 ppt |
For context: the PFOS average is higher than at 96% of the Oklahoma 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
Detected in 4 of 4 samples. Highest result 21.6 ppb. EPA's non-enforceable screening level is 10 ppb. Above 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: 2.6 ppb lead (Jan 2026 – now (in progress)). Below action level
Highest since 2016: 3 ppb (Dec 2023).
| Monitoring period | Lead (90th pct.) |
|---|---|
| Jan 2026 – now (in progress) | 2.6 ppb |
| Jan 2025 – Dec 2025 | 2.1 ppb |
| Jan 2024 – Dec 2024 | 2.1 ppb |
Earlier results (9)
| Jan 2023 – Dec 2023 | 3 ppb |
| Jan 2022 – Dec 2022 | 0 ppb |
| Jan 2021 – Dec 2021 | 0 ppb |
| Jan 2020 – Dec 2020 | 0 ppb |
| Jan 2016 – Dec 2018 | 0 ppb |
| Jan 2013 – Dec 2015 | 0 ppb |
| Jan 2010 – Dec 2012 | 0 ppb |
| Jan 2007 – Dec 2009 | 0 ppb |
| Jan 2004 – Dec 2006 | 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 |
|---|---|
| Feb 2023 2 times | 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 |
| Oct 2016 – Oct 2022 8 times | The system did not remove enough organic matter, which reacts with chlorine to form disinfection byproducts. EPA record: Carbon, total · Treatment Technique Precursor Removal · measured 0.98 ratio (limit TT ) Resolved |
| Jun 2016 – Oct 2018 2 times | The water was cloudier than allowed at least once. Cloudiness can shield germs from disinfection. Urgent public notice required What that means EPA record: Interim Enhanced Surface Water Treatment Rule · Single Turbidity Exceed (Enhanced SWTR) (limit ) Resolved |
| Apr 2017 – Oct 2018 4 times | The water was too cloudy too often in a month. Cloudiness can shield germs from disinfection. Urgent public notice required What that means EPA record: Interim Enhanced Surface Water Treatment Rule · Monthly Turbidity Exceed (Enhanced SWTR) (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 | 0.89 ppb | 300 ppb |
| Molybdenum | 2.76 ppb | 40 ppb |
| Strontium | 0.52 ppm | 1.5 ppm |
| Chromium-6 | 0.36 ppb | – |
| Vanadium | 9.64 ppb | 21 ppb |
Where it serves
ZIP codes the system reported serving: 74074, 74076
Nearby utilities
- Edmond Public Works Authority Edmond · 37 mi
- Midwest City Water System Midwest City · 49 mi
- Oklahoma City Utilities Oklahoma City · 52 mi
- Tri-County Rural Water District #2 Shawnee · 53 mi · PFAS above limit
- Moore Public Works Authority Moore · 60 mi
- Norman Utilities Authority Norman · 63 mi
Questions
Is Stillwater Utilities Authority water safe to drink?
Stillwater Utilities Authority had 16 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 Stillwater Utilities Authority water have PFAS?
Yes. EPA's 2023–2025 testing of Stillwater Utilities Authority found 5 PFAS at least once. The highest entry-point averages were above the federal limit for PFOS: PFOS 6.13 ppt (limit 4 ppt for PFOA and PFOS, 10 ppt for the others).
What is the lead level in Stillwater Utilities Authority water?
The most recent 90th-percentile lead result for Stillwater Utilities Authority is 2.6 ppb, for the monitoring period that began Jan 2026 (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 OK1021220: violations, enforcement and inspections, straight from EPA.
- EPA UCMR 5 data: the PFAS and lithium results (search the file for PWSID OK1021220).
- EPA SDWIS download: the lead results, population and violation records we use.
- The utility's annual water quality report (Consumer Confidence Report): ask Stillwater Utilities Authority at (405) 533-8452, 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.