Ontario City, OH
Lead detected, under the action levels
Latest 90th-percentile lead: 2.7 ppb (monitoring period 2023-2025). The federal action level is 15 ppb today and drops to 10 ppb in Nov 2027; EPA's health goal is 0. Lead was measured in sampled homes but the 90th percentile is under both action levels. EPA's health goal for lead is zero, so test your own tap if your home was built before 1986 or anyone in it is pregnant or a young child.
Ontario City at a glance
Ontario City serves about 6,756 people through 2,769 service connections, which makes it a medium-sized system under EPA's size classes. It is owned by a local government (city, town, county or district) and draws groundwater, in Richland County, Ohio. EPA system ID: OH7003512; phone on file: 567-437-5830. Call that number and ask whether your address has a lead, galvanized or unknown service line.
Ontario City's lead record
Against the period ending 2022 (3.4 ppb) the latest result is about the same. The highest 90th-percentile result EPA holds for Ontario City is 3.4 ppb across 5 monitoring periods, none of them over 15 ppb.
| Period ending | 90th-percentile lead |
|---|---|
| 2025 | 2.7 ppb |
| 2022 | 3.4 ppb |
| 2019 | 0 (not detected) |
| 2018 | 0 (not detected) |
| 2017 | 0 (not detected) |
Against other Ohio systems
Of the 1,079 Ohio systems with a lead result, the median latest reading is 0.7 ppb; 1 are over 15 ppb right now and 27 have gone over at some point. Ontario City's 2.7 ppb sits at the 85th percentile in Ohio and the 79th nationally (higher means more lead).
Other water systems in Richland County
44 other systems share Richland County; 9 of them have a higher latest lead result than Ontario City. If you are unsure which one supplies your house, the name on your water bill decides it.
| System | People | Latest lead |
|---|---|---|
| Mansfield City | 51,000 | 0 (not detected) |
| Shelby City | 9,453 | 0 (not detected) |
| Lexington Village | 4,825 | 0 (not detected) |
| Madison Water District | 2,050 | 0 (not detected) |
| Bellville Village | 1,918 | 0.9 ppb |
| Plymouth Village | 1,874 | 0 (not detected) |
| Eastview Community Water Association | 1,100 | 2.6 ppb |
| Butler Village | 940 | 1.1 ppb |
| Aqua Ohio - Mansfield System #01 | 813 | 0 (not detected) |
| Aqua Ohio - Mansfield System #07 | 766 | 0 (not detected) |
What to do in your house
Test your own tap with a certified lab first-draw sample; Ontario, OH may offer free or low-cost kits through the utility. If your own line is lead, replacing the private side runs about $1,200-$12,300 (EPA average about $4,700). Ask Ontario City whether it covers that cost before hiring anyone - many utilities now do.
These figures describe homes the utility sampled, not your tap. Only your service line record or a test of your own water answers the question for your house. Why sampled homes are the worst-case ones is in the guide to reading the number. Systems that went over once often dip back under; here is what that means.