Drinking water quality, OR
Oregon contaminants ranked by SDWA exceedance
Which regulated contaminants exceed their maximum contaminant level (MCL) most often across Oregon'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 | - | 4,615 | 0 | 319 |
| 1,1-dichloroethylene | - | 4,615 | 0 | 319 |
| 1,2,4-trichlorobenzene | - | 4,615 | 0 | 319 |
| 1,2-dibromo-3-chloropropane | - | 3,791 | 0 | 319 |
| 1,2-dichloroethane | - | 4,629 | 0 | 319 |
| 1,2-dichloropropane | - | 4,615 | 0 | 319 |
| 2,3,7,8-tcdd | - | 18 | 0 | 3 |
| 2,4,5-tp | - | 3,794 | 0 | 319 |
| 2,4-d | - | 3,881 | 0 | 319 |
| alachlor | - | 3,802 | 0 | 319 |
| antimony, total | inorganic | 1,632 | 0 | 305 |
| arsenic | inorganic | 3,799 | 0 | 312 |
| asbestos | - | 172 | 0 | 135 |
| atrazine | - | 3,800 | 0 | 319 |
| 1,1,1-trichloroethane | - | 4,615 | 0 | 319 |
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.