F0/100
Defiance Tap Water Quality: Is It Safe to Drink? (2026 Report)
Serving 18,154 residents · Ohio
What's In Defiance's Tap Water?
70
Contaminants Tested
1
Exceed EPA Limits
1
Above EPA Goals
2 contaminants above EPA health goals
| Contaminant | Detected | Limit (MCL) | Status |
|---|---|---|---|
Copper (90th percentile) | 60.00 mg/L | 1.30 mg/L | Over Limit |
Lead (90th percentile) | 0.003 mg/L | 0.015 mg/L | Above Goal |
EPA Violation History
5
Violations (last 5yr)
0
Unresolved
5
Health-Related
TIER 2Resolved
Exceeded the Maximum Contaminant Level (running average)
When: July 1, 2022 – September 30, 2022Rule: Stage 2 DBPREnforcement: Resolving — corrective action underway
TIER 2Resolved
Exceeded the Maximum Contaminant Level (running average)
When: April 1, 2022 – June 30, 2022Rule: Stage 2 DBPREnforcement: Formal — state order issued
TIER 2Resolved
Exceeded the Maximum Contaminant Level (running average)
When: January 1, 2022 – March 31, 2022Rule: Stage 2 DBPREnforcement: Formal — state order issued
TIER 2Resolved
Exceeded the Maximum Contaminant Level (running average)
When: October 1, 2021 – December 31, 2021Rule: Stage 2 DBPREnforcement: Formal — state order issued
TIER 2Resolved
Exceeded the Maximum Contaminant Level (running average)
When: July 1, 2021 – September 30, 2021Rule: Stage 2 DBPREnforcement: Formal — state order issued
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
DEFIANCE CITY
Population Served
16,494
Water Source
Surface Water
System ID
OH2000111
AYERSVILLE WATER AND SEWER DISTRICT
Population Served
1,660
Water Source
Purchased Surface Water
System ID
OH2000903
Frequently Asked Questions About Defiance Water
Is Defiance tap water safe to drink?
Defiance, Ohio tap water receives a grade of F (0/100), which is considered failing. 1 contaminant(s) exceed EPA maximum contaminant levels and 112 violation(s) are on record. Residents should consider using an NSF-certified water filter to reduce contaminant exposure.
What contaminants are in Defiance's water?
Of the 70 contaminants tested in Defiance's water supply, the most notable include Copper (90th percentile), Lead (90th percentile). 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 Defiance have any water quality violations?
Yes, Defiance has 112 EPA violation(s) on record, with the most recent in 2024. Violation types include Other, MCL, MR. 78 of these are health-based violations, which are the most serious category.
Do I need a water filter in Defiance?
Based on EPA data, using a water filter in Defiance 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 Defiance's tap water come from?
Defiance's drinking water is sourced from surface water and supplied by DEFIANCE CITY and 1 other water system(s). The system serves approximately 18,154 people. Surface water sources include rivers, lakes, and reservoirs.
How often is Defiance'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. Defiance'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 Defiance's water compare to other cities in Ohio?
Defiance's water quality score of 0/100 earns a grade of F, which is considered failing. This is a concerning score that suggests significant water quality issues. Visit our Ohio state page to see how all cities in the state compare.
What should I do if I'm concerned about Defiance's water quality?
If you have concerns about Defiance'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 (DEFIANCE CITY) 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.