Water Quality in Hollis, OK: 29 Violations — Grade C
Grade C · Score 65/100 · 3 water systems · Updated 2026-05-03
Hollis's water has moderate compliance issues. Residents in affected areas should consider filtration.
Data: EPA Safe Drinking Water Information System (SDWIS) Last verified: 2026-05-03
The compliance record maintained by the EPA for Hollis, OK documents 29 water violations — each tied to a specific public water system and assigned a violation category in the federal Safe Drinking Water dataset.
Water Quality by ZIP Code in Hollis
Water quality varies across Hollis's 1 ZIP codes. Check your specific ZIP for detailed contaminant data.
| ZIP Code | Grade | Score | Violations | Health | |
|---|---|---|---|---|---|
| 73550 | C | 65 | 29 | 17 | View report → |
Violation Trend
EPA violations recorded for water systems serving Hollis.
Water Quality Overview
Hollis, Oklahoma receives a water quality grade of C with an overall score of 65 out of 100, based on EPA compliance data from the Safe Drinking Water Information System (SDWIS).
The 3 water systems serving Hollis have accumulated 29 EPA violations, including 17 health-based violations. These violations are tracked across 1 ZIP codes serving approximately 2,533 people.
What Grade C Means
A grade of C indicates moderate compliance issues. Hollis's water systems have some violations that warrant attention. While the water may still be safe for most people, residents in affected ZIP codes should consider additional testing or filtration.
Lead Levels
The average 90th percentile lead level across Hollis water systems is 0.0026 mg/L — within EPA limits. No ZIP codes exceed the EPA lead action level.
With 80% of homes built before 1986, Hollis has a higher-than-average risk of lead from older plumbing. Lead solder was banned in 1986, and homes built before this date may have lead in pipes, solder joints, or fixtures.
Water Systems Serving Hollis
Hollis is served by 3 community water systems regulated under the Safe Drinking Water Act. These systems collectively serve approximately 2,533 people across 1 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 10 enforcement actions against water systems serving Hollis. Enforcement actions range from informal compliance assistance to formal orders and penalties.
How to Check Your Water in Hollis
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 Hollis Water Systems
The following contaminants have been detected or caused violations across Hollis's water systems:
| Contaminant | Category | MCL | Violations | ZIPs Affected | Health-Based |
|---|---|---|---|---|---|
| Arsenic | Inorganic | 0.01 mg/L | 17 | 1 | Yes |
| Revised Total Coliform Rule | Microbiological | N/A | 3 | 1 | No |
| Total Trihalomethanes (TTHM) | Disinfection Byproducts | 0.08 mg/L | 1 | 1 | No |
| Stage 1 DBP Rule | Treatment Technique | N/A | 1 | 1 | No |
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 Hollis:
| Year | Total Violations | Health-Based |
|---|---|---|
| 2021 | 2 | 2 |
| 2022 | 4 | 4 |
| 2023 | 3 | 3 |
| 2024 | 4 | 4 |
| 2025 | 2 | 2 |
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 Hollis. Recent actions:
| Date | Action Type |
|---|---|
| 2025-08-29 | State Order Extension |
| 2025-06-25 | State Informal Action |
| 2025-06-09 | State Order Extension |
| 2025-05-19 | State Informal Action |
| 2025-05-02 | State Informal Action |
| 2025-05-02 | State Informal Enforcement |
| 2025-05-01 | State Informal Action |
| 2025-03-07 | State Informal Action |
| 2025-03-07 | State Informal Enforcement |
| 2025-03-06 | State Informal Action |
Enforcement actions range from informal compliance assistance to formal orders and penalties. The most recent action was on 2025-08-29.
Hollis vs. Nearby Oklahoma Cities
How Hollis's water quality compares to similar cities in Oklahoma:
| City | Grade | Violations | Systems | Population |
|---|---|---|---|---|
| Hollis | C | 29 | 3 | 2,533 |
| Agra | A | 6 | 1 | 2,525 |
| Ramona | B | 47 | 4 | 2,516 |
| Wainwright | C | 18 | 1 | 2,550 |
Common Questions About Hollis Water
These are the most common questions residents search for about water quality in Hollis, Oklahoma:
Is Hollis water hard or soft? Water hardness varies by source. Hollis's 3 water systems use multiple sources. Check your ZIP code report for specific hardness data.
Can I drink Hollis tap water? Hollis's water receives a grade of C (65/100). There are 17 health-based violations — consider filtration.
What is the best water filter for Hollis? A NSF/ANSI 53-certified filter for lead removal is a good general choice. See our Water Filter Matcher for personalized recommendations.
Hollis vs. Oklahoma Average
Understanding how Hollis 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 Hollis.
ZIP Codes in Hollis
Hollis spans 1 ZIP code. The ZIP with the lowest water quality score is 73550. 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.