Is Stillwater, OK tap water safe?

Data: U.S. EPA · How we read the data · How we check it

Stillwater Utilities Authority, the largest system here, had PFAS above the 2024 federal limits (PFOS) in EPA's 2023–2025 testing.

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 issues a boil-water or do-not-drink notice, follow it.

2 public water systems serve parts of Stillwater. The largest, Stillwater Utilities Authority, serves 53,000 people, and one system here had PFAS above a federal limit. Your water bill names your system.

Largest system

Stillwater Utilities Authority

53,000 people · Surface water · EPA ID OK1021220

PFAS	Highest average	Limit	Status
PFOA Not detected	–	4 ppt	Not detected
PFOS Above limit	6.13 ppt	4 ppt	Above limit
PFHxS Detected, below limit	4.58 ppt	10 ppt	Detected, below limit
PFNA Not detected	–	10 ppt	Not detected
HFPO-DA (GenX) Not detected	–	10 ppt	Not detected

ppt = parts per trillion. "Highest average" is the highest average at any of the system's entry points, the way EPA compares results with the limits.

For context: the PFOS average is higher than at 96% of the Oklahoma systems EPA tested.

Lead: 2.6 ppb at the 90th percentile (Nov 2026, and 9 in 10 homes sampled were at or below it) Below action level
Health-based violations since 2016: 16

Full Stillwater Utilities Authority results

Across Oklahoma, 8 of 167 water systems EPA tested had PFAS above a 2024 federal limit, and 5 systems were above the lead action level in results from the last five years. Oklahoma results.

Stillwater homes and lead pipes

44%

of homes built before 1980 (Oklahoma 49%, US 50%)

built before 1950 (Oklahoma 12%)

63%

of households rent (Oklahoma 34%)

Lead service lines and lead solder were allowed until 1986, so homes from before then are the ones to check. Renting? Ask your landlord what the service line is made of, because it's their pipe to replace. How to check your own line.

Housing: Census American Community Survey 2020–2024 5-year estimates for Stillwater city (tables B25034, B25003). Estimates for small places have a margin of error.

Which system serves your ZIP code

Based on the ZIP codes each system reported serving. Boundaries don't follow ZIP lines exactly, so your water bill is the final word.

System	ZIP codes in Stillwater
Stillwater Utilities Authority 53,000 people	74075, 74077
OSU Water Plant 13,000 people	74078

Other water systems serving Stillwater

OSU Water Plant
13,000 people · Surface water · Oklahoma · reported ZIPs here
Total trihalomethanes (TTHM) violations

How nearby cities compare

City	Main water system	PFAS	Lead (90th pct.)
Edmond 37 mi Edmond Public Works Authority	Edmond Public Works Authority	None above limits	0 ppb
Enid 48 mi Enid Water System	Enid Water System	None above limits	5.1 ppb
Midwest City 49 mi Midwest City Water System	Midwest City Water System	None above limits	1.2 ppb
Oklahoma City 52 mi Oklahoma City Utilities	Oklahoma City Utilities	None above limits	0 ppb
Shawnee 53 mi Shawnee Municipal Authority	Shawnee Municipal Authority	None above limits	2.8 ppb
Yukon 57 mi Yukon Water System	Yukon Water System	None above limits	0 ppb

Questions

Is Stillwater tap water safe to drink?

Stillwater Utilities Authority had 16 health-based violations since 2016, and EPA testing found PFAS above the 2024 federal limits, which it must meet by 2029. Utility data can't show lead from your own pipes: if your home was built before 1986, test your tap. Your utility's annual Consumer Confidence Report is the official summary.

Who supplies water in Stillwater, OK?

2 public water systems serve parts of Stillwater. The largest is Stillwater Utilities Authority (53,000 people). Your water bill names your system. The EPA ID is also on your utility's Consumer Confidence Report.

Does Stillwater tap water have PFAS?

Yes. EPA's 2023–2025 testing found entry-point averages above the 2024 federal limits for PFOS at Stillwater Utilities Authority. Systems have until 2029 to meet them.

Do Stillwater homes have lead pipes?

Census estimates put 44% of Stillwater homes as built before 1980 (Oklahoma: 49%). Lead service lines and lead solder were allowed until 1986, so older homes are more likely to have them. Stillwater Utilities Authority's service line inventory says what your line is made of. The only way to know for your home is to check the line where it enters the house and test your tap.

Source: U.S. EPA drinking water records and PFAS testing (UCMR 5). How we read the data.