01The verdict: is Oak Harber water safe?
Oak Harber's tap water meets most EPA standards but has areas that warrant attention. With a grade of B+ (84.2/100), some contaminant levels or compliance issues suggest that residents may benefit from additional filtration. The city's 1 water system serves approximately 2,288 residents using surface water (rivers, lakes, or reservoirs).
Copper is over its legal limit
Measured at 665.00 mg/L against the EPA Action Level of 1.3 mg/L. The ledger below shows how far over — and which filter removes it.
See the measurement ↓Lead is well under the limit
90th-percentile lead is 0.0 ppb — beneath the 15 ppb federal action level and under the 5 ppb watch threshold.
See the trend ↓2 violations in the last five years
Recent compliance history is the best predictor of future problems — the year-by-year record is below.
See the record ↓Oak Harber's drinking water received a grade of B+ (84.2 out of 100), indicating good water quality. The city's 1 water system serves approximately 2,288 residents using surface water.
Lead levels were measured at 0.0 ppb (90th percentile), well within EPA limits. This system has not yet been tested for PFAS under the EPA UCMR 5 program. The system has 9 violations on record, including 2 health-based violations. 2 remain unresolved.
Oak Harber ranks #158 out of 511 cities in Ohio for water quality, placing it mid-range in the state. The city draws from surface water sources, which are more susceptible to seasonal runoff and agricultural contamination, requiring extensive multi-barrier treatment including coagulation, filtration, and disinfection. As a small community water system, Oak Harber may have fewer resources for advanced treatment technologies and infrastructure upgrades compared to larger utilities.
02What's in Oak Harber's water
Every contaminant flagged in Oak Harber, on one shared scale: distance to its own legal limit. The red line is the limit — anything past it is out of compliance, and the closer a bar gets, the less headroom the system has.
Over Limit — EPA Action Level: 1.3 mg/L
Exceeds the EPA action level. Copper leaches from household plumbing — flush taps for 30 seconds before drinking, and consider a certified filter.Full contaminants report
| Contaminant | Detected Level | EPA Limit | Unit | Category | Status |
|---|---|---|---|---|---|
| Lead (90th percentile) LeadHeavy Metal A toxic heavy metal that can leach into drinking water from older pipes, solder, and fixtures. No amount of lead in water is considered safe. Health EffectsBrain and nervous system damage in children, kidney damage, high blood pressure, and reproductive problems in adults. EPA Limit15 ppb action level Common SourcesCorrosion of lead pipes, lead solder, brass faucets, and household plumbing. | 0.0 | 15 | ppb | Inorganic | Safe |
| Copper (90th percentile) CopperInorganic A metal that enters drinking water mainly through corrosion of copper plumbing. Small amounts are essential for health, but excess levels are harmful. Health EffectsGastrointestinal distress (nausea, vomiting, diarrhea) at short-term high levels; liver and kidney damage from long-term exposure. EPA Limit1.3 mg/L action level Common SourcesCorrosion of copper household plumbing, erosion of natural deposits. | 665.00 | 1.3 | mg/L | Inorganic | Over Limit |
Cities ranked by 90th-percentile lead PF PFAS in Ohio
Cities ranked by compounds detected Cu Copper in Ohio
Cities ranked by 90th-percentile copper
03Oak Harber's ten-year track record
Each box is one year. A green check means no EPA violations; a numbered badge counts that year's violations — red if any were health-based, amber if they were monitoring or paperwork issues. The system has 9 violations on record, including 2 health-based violations. 2 remain unresolved.
7 of the last ten years were clean. The numbered years had EPA violations — red when any were health-based, amber when they were paperwork or missed-testing issues.
▼ Down 10 ppb since 1999. Latest reading: 0 ppb (2025) — 0% of the action level. Sampled at higher-risk homes (90th percentile).
▲ Up 664 mg/L since 1999. The latest reading (665 mg/L, 2004) is over the action level. Sampled at higher-risk homes (90th percentile).
04Where Oak Harber's water comes from
Oak Harber's drinking water comes primarily from surface water sources such as rivers, lakes, or reservoirs.
Surface Water
Rivers, lakes, or reservoirs — more exposed to runoff, agriculture, and seasonal swings than groundwater.
Local treatment
Multi-barrier treatment: coagulation, sedimentation, filtration, and disinfection to meet EPA standards.
1 system
1 water system, operated under local government ownership.
2,288 people
Residents served across Oak Harber's service area.
Surface water systems require multi-stage treatment including coagulation, sedimentation, filtration, and disinfection to meet EPA Safe Drinking Water Act standards. These sources can be impacted by seasonal changes, stormwater runoff, upstream agriculture, and industrial discharge. The system is operated by local government ownership and serves approximately 2,288 people through 1 water system.
| System name | PWSID | Population | Source |
|---|---|---|---|
| CARROLL WATER AND SEWER | OH6205111 | 2,288 | Surface Water |
05How Oak Harber compares
Scores for nearby Ohio cities on one line, with the average marked.
dashed line = Ohio average (58/100)
Oak Harber scores 84.2/100 — above the Ohio average of 58/100. It outscores 9 of 10 nearby cities. Full Ohio rankings →
35.5 / 100ACleveland, OH
85.5 / 100FCincinnati, OH
36.8 / 100BToledo, OH
78 / 100FKent, OH
38.2 / 100CKettering, OH
64.6 / 100
Compare all cities in the county — grades, violations, and contaminant data side by side.→
06What to do at home
Steps matched to what testing actually found in Oak Harber's water — not generic advice.
Filter drinking & cooking water
Basic carbon filter for extra protection. Copper exceeds the EPA action level of 1.3 mg/L
Compare tested filters →Read your utility's annual report
Every utility must publish a yearly Consumer Confidence Report with its own testing results. It pairs well with the independent data on this page.
How to read a CCR →Watch for Oak Harber alerts
We refresh EPA data monthly and surface new violations, advisories, and boil-water notices for your county on this page.
All water alerts →Frequently asked questions
Is Oak Harber, OH tap water safe to drink?
Oak Harber's water quality earned a grade of B+ (84.2/100). The water generally meets EPA standards and is considered safe for consumption. The city ranks #158 out of 511 cities tested in Ohio.
What contaminants are in Oak Harber's water?
Lead was measured at 0.0 ppb (90th percentile). 9 violations are on record.
How is Oak Harber's water quality grade calculated?
The grade is based on four factors: violation history (40%), lead and copper levels (25%), PFAS contamination (25%), and regulatory compliance (10%). The score is also adjusted based on how complete the available data is. See our methodology page for full details.
Do I need a water filter in Oak Harber?
Based on current data, basic filtration should suffice for additional peace of mind.
Where does Oak Harber's water come from?
Oak Harber's water is sourced from Surface water. The city has 1 water system serving approximately 2,288 residents.
What health violations has Oak Harber's water system had?
Oak Harber has 2 health-based violations on record. The most recent violation was recorded in December 2024. Health-based violations mean the water exceeded EPA maximum contaminant levels (MCLs) for a regulated substance. 2 violations remain unresolved.
How does Oak Harber's water compare to other cities?
Oak Harber ranks #158 out of 511 cities in Ohio (better than 69% of state cities) and #5999 out of 15382 cities nationally (61th percentile). The grade of B+ reflects the combined assessment of violation history, lead and copper levels, PFAS contamination, and regulatory compliance.
Does Oak Harber's small water system affect quality?
Oak Harber's system serves approximately 2,288 residents. Small community water systems (under 3,300 people) may have fewer financial resources for infrastructure upgrades and advanced treatment technologies. However, they are held to the same EPA drinking water standards as larger systems. This system has 9 violations on record.