Drinking water quality, OH
Ohio contaminants ranked by SDWA exceedance
Which regulated contaminants exceed their maximum contaminant level (MCL) most often across Ohio's community water systems, per EPA's Six-Year Review sample-level dataset (2012-2019). Source data is public; every value is citable.
Top 15 contaminants by exceedance count
| Contaminant | Category | Samples | Above MCL | Munis affected |
|---|---|---|---|---|
| 1,1,2-trichloroethane | - | 8,120 | 0 | 657 |
| 1,1-dichloroethylene | - | 8,119 | 0 | 657 |
| 1,2,4-trichlorobenzene | - | 8,118 | 0 | 657 |
| 1,2-dibromo-3-chloropropane | - | 102 | 0 | 51 |
| 1,2-dichloroethane | - | 8,118 | 0 | 657 |
| 1,2-dichloropropane | - | 8,120 | 0 | 657 |
| 2,3,7,8-tcdd | - | 63 | 0 | 22 |
| 2,4,5-tp | - | 13 | 0 | 10 |
| 2,4-d | - | 289 | 0 | 84 |
| alachlor | - | 5,707 | 0 | 658 |
| antimony, total | inorganic | 5,023 | 0 | 656 |
| arsenic | inorganic | 11,736 | 0 | 656 |
| asbestos | - | 227 | 0 | 180 |
| atrazine | - | 5,706 | 0 | 658 |
| 1,1,1-trichloroethane | - | 8,132 | 0 | 657 |
For citizens
Look up your own water system by name on the muni search, then read the drinking-water quality band on its profile page for per-contaminant readings + MCL ratios.
For chemical suppliers
Contaminants near or above MCL signal treatment-chemical procurement pressure. Lane intelligence pairs this with per-chemical bid timing on the supplier tier.