Water Quality in Stillwater, OK: 50 Violations — Grade B
Grade B · Score 73/100 · 5 water systems · Updated 2026-05-03
Stillwater's water is mostly safe. Minor violations exist but are primarily monitoring-related.
Data: EPA Safe Drinking Water Information System (SDWIS) Last verified: 2026-05-03
On record with EPA: Stillwater, OK has 50 water violations.
Water Quality Map: Stillwater, OK
Each dot represents a ZIP code. Color indicates water quality grade. Tap a dot for details.
Water Quality by ZIP Code in Stillwater
Water quality varies across Stillwater's 5 ZIP codes. Check your specific ZIP for detailed contaminant data.
| ZIP Code | Grade | Score | Violations | Health | |
|---|---|---|---|---|---|
| 74074 | B | 70 | 10 | 8 | View report → |
| 74075 | B | 70 | 10 | 8 | View report → |
| 74077 | B | 74 | 10 | 8 | View report → |
| 74078 | B | 74 | 10 | 8 | View report → |
| 74076 | B | 75 | 10 | 8 | View report → |
Violation Trend
EPA violations recorded for water systems serving Stillwater.
Water Quality Overview
Stillwater, Oklahoma receives a water quality grade of B with an overall score of 73 out of 100, based on EPA compliance data from the Safe Drinking Water Information System (SDWIS).
The 5 water systems serving Stillwater have accumulated 50 EPA violations, including 40 health-based violations. These violations are tracked across 5 ZIP codes serving approximately 72,900 people.
What Grade B Means
A grade of B indicates good compliance with EPA drinking water standards. While not perfect, Stillwater's water systems meet the vast majority of federal requirements. Minor violations may exist but typically relate to monitoring or reporting rather than health-based standards.
Lead Levels
The average 90th percentile lead level across Stillwater water systems is 0.0021 mg/L — within EPA limits. No ZIP codes exceed the EPA lead action level.
Water Systems Serving Stillwater
Stillwater is served by 5 community water systems regulated under the Safe Drinking Water Act. These systems collectively serve approximately 72,900 people across 5 ZIP codes.
Each water system is identified by a Public Water System ID (PWSID) and is required to:
- Test for over 90 regulated contaminants on a regular schedule
- Report results to the EPA and state regulators
- Issue an annual Consumer Confidence Report (CCR) to all customers
- Take corrective action when violations occur
The EPA has taken 50 enforcement actions against water systems serving Stillwater. Enforcement actions range from informal compliance assistance to formal orders and penalties.
How to Check Your Water in Stillwater
Enter your ZIP code on ZipCheckup to see your specific water system data, including contaminant levels, violation history, and safety scores
Request your CCR — your water utility must provide an annual Consumer Confidence Report with detailed test results for all monitored contaminants
Get a home test — certified kits cost $20–$50 and test for lead, bacteria, and common contaminants. Professional lab tests ($150–$400) cover a broader panel
Consider filtration — NSF-certified filters can remove specific contaminants. Reverse osmosis removes the broadest range; activated carbon is effective for chlorine and many organics
Check for advisories — monitor your local utility website and local news for boil water advisories or system alerts
Contaminants Detected in Stillwater Water Systems
The following contaminants have been detected or caused violations across Stillwater's water systems:
| Contaminant | Category | MCL | Violations | ZIPs Affected | Health-Based |
|---|---|---|---|---|---|
| Chlorite | Disinfection Byproducts | 1 mg/L | 20 | 5 | Yes |
| E. coli | Microbiological | N/A | 15 | 5 | Yes |
| Haloacetic Acids (HAA5) | Disinfection Byproducts | 0.06 mg/L | 10 | 5 | Yes |
MCL = Maximum Contaminant Level (EPA enforceable standard). Health-based violations indicate levels that may pose direct health risks.
Violation Trend Over Time
Year-by-year EPA violations recorded for water systems serving Stillwater:
| Year | Total Violations | Health-Based |
|---|---|---|
| 2021 | 5 | 5 |
| 2022 | 15 | 15 |
| 2023 | 15 | 15 |
| 2025 | 5 | 5 |
Violation counts have remained stable over the observed period.
EPA Enforcement History
The EPA and state regulators have taken 10 enforcement actions against water systems serving Stillwater. Recent actions:
| Date | Action Type |
|---|---|
| 2025-09-04 | State Informal Enforcement |
| 2025-09-04 | State Filed Suit |
| 2025-07-29 | State Informal Action |
| 2025-07-14 | State Order Extension |
| 2025-06-27 | State Informal Action |
| 2025-04-02 | State Order Extension |
| 2025-03-06 | State Informal Action |
| 2025-03-06 | State Informal Enforcement |
| 2024-02-09 | State Informal Action |
| 2024-02-01 | State Order Extension |
Enforcement actions range from informal compliance assistance to formal orders and penalties. The most recent action was on 2025-09-04.
Stillwater vs. Nearby Oklahoma Cities
How Stillwater's water quality compares to similar cities in Oklahoma:
| City | Grade | Violations | Systems | Population |
|---|---|---|---|---|
| Stillwater | B | 50 | 5 | 72,900 |
| Edmond | A | 30 | 5 | 88,164 |
| Enid | A | 75 | 5 | 53,800 |
| Claremore | B | 39 | 5 | 52,250 |
Water Quality by ZIP Code in Stillwater
Water quality varies across Stillwater's ZIP codes. The table below shows the worst-scoring and best-scoring areas:
| ZIP Code | Score | Grade | Violations | Health-Based |
|---|---|---|---|---|
| 74074 | 70 | B | 10 | 8 |
| 74075 | 70 | B | 10 | 8 |
| 74077 | 74 | B | 10 | 8 |
| 74078 | 74 | B | 10 | 8 |
| 74076 | 75 | B | 10 | 8 |
Common Questions About Stillwater Water
These are the most common questions residents search for about water quality in Stillwater, Oklahoma:
Is Stillwater water hard or soft? Water hardness varies by source. Stillwater's 5 water systems use multiple sources. Check your ZIP code report for specific hardness data.
Can I drink Stillwater tap water? Stillwater's water receives a grade of B (73/100). There are 40 health-based violations — consider filtration.
What is the best water filter for Stillwater? A NSF/ANSI 53-certified filter for lead removal is a good general choice. See our Water Filter Matcher for personalized recommendations.
Stillwater vs. Oklahoma Average
Understanding how Stillwater compares to the broader Oklahoma average helps contextualize your local water quality. Factors like water source, treatment methods, and infrastructure age all contribute to differences between cities in the same state.
To see how individual neighborhoods compare, check the ZIP code reports below — water quality can vary significantly even within Stillwater.
ZIP Codes in Stillwater
Stillwater spans 5 ZIP codes. The ZIP with the lowest water quality score is 74074. Each ZIP code has its own water quality profile based on the specific water system serving that area. Check each ZIP code for detailed contaminant data, violation history, and system information.
Data Sources
- Water quality: EPA Safe Drinking Water Information System (SDWIS)
- Lead/copper: EPA Lead and Copper Rule sampling data
- Radon: EPA Map of Radon Zones
- Enforcement: EPA ECHO database
- Filter recommendations: NSF/ANSI certified products
Updated daily.
Frequently Asked Questions
Your Water is Safe — Here's How to Keep It That Way
Grade B is excellent news. Here's what proactive homeowners do to maintain water quality:
Annual Water Testing
EPA recommends annual testing even with clean water. Home test kits: $20-$50. Catches changes before they become problems.
Maintenance Filtration
A basic carbon filter removes chlorine taste and catches emerging contaminants like PFAS that aren't yet fully regulated.
Plumbing Check
Even safe city water picks up lead from home pipes. If your home was built before 1986, a one-time pipe inspection is recommended.