D31/100
Stillwater Tap Water Quality: Is It Safe to Drink? (2026 Report)
Serving 72,900 residents · Oklahoma
What's In Stillwater's Tap Water?
69
Contaminants Tested
1
Exceed EPA Limits
1
Above EPA Goals
2 contaminants above EPA health goals
| Contaminant | Detected | Limit (MCL) | Status |
|---|---|---|---|
PFOS | 0.006 µg/L | 0.004 µg/L | Over Limit |
Lead (90th percentile) | 0.002 mg/L | 0.015 mg/L | Above Goal |
EPA Violation History
6
Violations (last 5yr)
0
Unresolved
6
Health-Related
TIER 2Resolved
Failed treatment technique requirements
When: February 1, 2023 – February 28, 2023Rule: Surface Water Treatment RuleEnforcement: Formal — state order issued
TIER 2Resolved
Failed treatment technique requirements
When: February 1, 2023 – February 28, 2023Rule: Surface Water Treatment RuleEnforcement: Formal — state order issued
TIER 2Resolved
Treatment Technique Violation
When: October 1, 2022 – December 31, 2022Rule: Stage 1 DBPREnforcement: Formal — state order issued
TIER 2Resolved
Treatment Technique Violation
When: July 1, 2022 – September 30, 2022Rule: Stage 1 DBPREnforcement: Formal — state order issued
TIER 2Resolved
Treatment Technique Violation
When: January 1, 2022 – March 31, 2022Rule: Stage 1 DBPREnforcement: Formal — state order issued
TIER 2Resolved
Treatment Technique Violation
When: October 1, 2021 – December 31, 2021Rule: Stage 1 DBPREnforcement: Resolving — corrective action underway
Understanding violation severity
Tier 1Urgent health risk. Utility must notify all customers within 24 hours.Tier 2Important health or treatment issue. Customers notified within 30 days.Tier 3Administrative or monitoring issue. Reported in the annual water quality report.
Source: EPA Safe Drinking Water Information System (SDWIS) · Updated quarterly
Water Utility Details
OSU WATER PLANT
Population Served
13,000
Water Source
Surface Water
System ID
OK1020910
STILLWATER UTILITIES AUTHORITY
Population Served
53,000
Water Source
Surface Water
System ID
OK1021220
PAYNE CO RWD #3
Population Served
1,400
Water Source
Purchased Surface Water
System ID
OK2006011
51 EAST WATER
Population Served
2,500
Water Source
Purchased Surface Water
System ID
OK3006003
PAYNE CO RW CORP #3
Population Served
3,000
Water Source
Purchased Surface Water
System ID
OK3006030
Frequently Asked Questions About Stillwater Water
Is Stillwater tap water safe to drink?
Stillwater, Oklahoma tap water receives a grade of D (31/100), which is considered poor. 2 contaminant(s) exceed EPA maximum contaminant levels and 151 violation(s) are on record. Residents should consider using an NSF-certified water filter to reduce contaminant exposure.
What contaminants are in Stillwater's water?
Of the 70 contaminants tested in Stillwater's water supply, the most notable include Copper (90th percentile), PFOS, Lead (90th percentile). 2 contaminant(s) exceed EPA legal limits (MCLs). 3 contaminant(s) exceed EPA health goals (MCLGs), which are non-enforceable targets set at levels with no known health risk.
Does Stillwater have any water quality violations?
Yes, Stillwater has 151 EPA violation(s) on record, with the most recent in 2025. Violation types include MR, MCL, TT. 66 of these are health-based violations, which are the most serious category.
Do I need a water filter in Stillwater?
Based on EPA data, using a water filter in Stillwater is recommended. 2 contaminant(s) exceed legal limits. An NSF-certified filter — such as a reverse osmosis or activated carbon system — can effectively reduce many common contaminants. Choose a filter certified to remove the specific contaminants found in your area.
Where does Stillwater's tap water come from?
Stillwater's drinking water is sourced from surface water and supplied by OSU WATER PLANT and 4 other water system(s). The system serves approximately 72,900 people. Surface water sources include rivers, lakes, and reservoirs.
How often is Stillwater's water tested?
Under the Safe Drinking Water Act (SDWA), water utilities are required to regularly test for over 90 contaminants. Testing frequency varies by contaminant — some are tested monthly, others quarterly or annually. Stillwater's water systems must report results to the EPA and publish an annual Consumer Confidence Report (CCR). The data on this page reflects the latest available EPA testing data.
How does Stillwater's water compare to other cities in Oklahoma?
Stillwater's water quality score of 31/100 earns a grade of D, which is considered poor. This is a concerning score that suggests significant water quality issues. Visit our Oklahoma state page to see how all cities in the state compare.
What should I do if I'm concerned about Stillwater's water quality?
If you have concerns about Stillwater's tap water, consider these steps: (1) Request your utility's annual Consumer Confidence Report for detailed local data. (2) Get your water independently tested through a state-certified laboratory. (3) Consider an NSF-certified water filter rated for the contaminants found in your area. (4) Contact your water utility (OSU WATER PLANT) with specific questions. (5) Report water quality issues to your state drinking water program or the EPA Safe Drinking Water Hotline at 800-426-4791.