C40/100
Collinsville Tap Water Quality: Is It Safe to Drink? (2026 Report)
Serving 30,775 residents · Oklahoma
What's In Collinsville's Tap Water?
69
Contaminants Tested
0
Exceed EPA Limits
1
Above EPA Goals
1 contaminant above EPA health goals
| Contaminant | Detected | Limit (MCL) | Status |
|---|---|---|---|
chlorate | 459.00 µg/L | — | Above Goal |
EPA Violation History
4
Violations (last 5yr)
0
Unresolved
0
Health-Related
TIER 3Resolved
Failed Level 2 Assessment under Revised Total Coliform Rule
This is a paperwork/process violation — it does not mean a contaminant was detected at unsafe levels.
When: June 1, 2025 – June 30, 2025Rule: Stage 1 DBPREnforcement: Resolving — corrective action underway
TIER 3Resolved
Monitoring Violation
This is a paperwork/process violation — it does not mean a contaminant was detected at unsafe levels.
When: June 1, 2025 – June 30, 2025Rule: Total Coliform RuleEnforcement: Resolving — corrective action underway
TIER 3Resolved
Failed Level 2 Assessment under Revised Total Coliform Rule
This is a paperwork/process violation — it does not mean a contaminant was detected at unsafe levels.
When: May 1, 2025 – May 31, 2025Rule: Stage 1 DBPREnforcement: Resolving — corrective action underway
TIER 3Resolved
Monitoring Violation
This is a paperwork/process violation — it does not mean a contaminant was detected at unsafe levels.
When: May 1, 2025 – May 31, 2025Rule: Total Coliform RuleEnforcement: 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
WASHINGTON CO RWD #3 (NEW,#1)
Population Served
25,375
Water Source
Surface Water
System ID
OK1021418
COLLINSVILLE
Population Served
5,400
Water Source
Surface Water
System ID
OK1021505
Frequently Asked Questions About Collinsville Water
Is Collinsville tap water safe to drink?
Collinsville, Oklahoma tap water receives a grade of C (40/100), which is considered fair. 1 contaminant(s) exceed EPA maximum contaminant levels and 53 violation(s) are on record. Residents should consider using an NSF-certified water filter to reduce contaminant exposure.
What contaminants are in Collinsville's water?
Of the 70 contaminants tested in Collinsville's water supply, the most notable include Copper (90th percentile), chlorate. 1 contaminant(s) exceed EPA legal limits (MCLs). 2 contaminant(s) exceed EPA health goals (MCLGs), which are non-enforceable targets set at levels with no known health risk.
Does Collinsville have any water quality violations?
Yes, Collinsville has 53 EPA violation(s) on record, with the most recent in 2025. Violation types include MR, MON, RPT. 24 of these are health-based violations, which are the most serious category.
Do I need a water filter in Collinsville?
Based on EPA data, using a water filter in Collinsville is recommended. 1 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 Collinsville's tap water come from?
Collinsville's drinking water is sourced from surface water and supplied by WASHINGTON CO RWD #3 (NEW,#1) and 1 other water system(s). The system serves approximately 30,775 people. Surface water sources include rivers, lakes, and reservoirs.
How often is Collinsville'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. Collinsville'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 Collinsville's water compare to other cities in Oklahoma?
Collinsville's water quality score of 40/100 earns a grade of C, which is considered fair. This is a below-average score that indicates room for improvement. Visit our Oklahoma state page to see how all cities in the state compare.
What should I do if I'm concerned about Collinsville's water quality?
If you have concerns about Collinsville'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 (WASHINGTON CO RWD #3 (NEW,#1)) 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.