Drinking water quality · 2024
· Verified
· PWSID OH5703512
What's in Dayton, OH tap water
1 contaminant in Dayton, OH's water sat at or above a federal limit, led by PFOS (Perfluorooctane sulfonic acid) at 2.5x the limit.
- !1 contaminant at or above a federal limit — worst is PFOS (Perfluorooctane sulfonic acid) at 2.5x
- !2 contaminants within 20% of a limit
- !10 of 27 core regulated contaminants reported — 17 never appear in this report
- ✓No open federal violations
+How this score is calculated
Every system starts at 100. Points come off for measured levels, for the federal violation record, and for how much of the core regulated set the utility actually reported. All three inputs are the utility's own published numbers and EPA's own records.
- −28 contaminants at or above a federal limit
- −8 contaminants within 20% of a limit
- −0 open health-based violations
- −0 open monitoring / reporting violations
- −0 health-based violations resolved in the last 5 years
- −14 core regulated contaminants never reported (10/27)
A 90–100 · B 80–89 · C 70–79 · D 60–69 · F below 60. A system reporting under a third of the core set is capped at C however clean its numbers look — a short report is not a clean bill of health.
Full grading methodology, constant for constant →What to worry about
- PFOS (Perfluorooctane sulfonic acid)2.5× the federal limit10 ng/L · limit 4 ng/L
Linked to cancer, thyroid disease, and immune effects; the EPA set an enforceable limit of 4 parts per trillion.
higher than 80% of U.S. systems
- PFHxS (Perfluorohexane sulfonic acid)98% of the federal limit9.799999999999999 ng/L · limit 10 ng/L
Regulated by the EPA at 10 parts per trillion and included in the PFAS Hazard Index.
higher than 80% of U.S. systems
- PFOA89% of the federal limit3.57 ng/L · limit 4 ng/L
Linked to cancer, liver damage, and immune effects; the EPA set an enforceable limit of 4 parts per trillion.
higher than 35% of U.S. systems
+17 contaminants were measured and came in below the limitShow all
| Contaminant | Measured | Federal limit |
|---|---|---|
| TTHM | 28.3 ug/L | 80 ug/L |
| Chlorine | 1.23–1.32 mg/L | 4 mg/L |
| Fluoride | 0.82–1.18 mg/L | 4 mg/L |
| Nitrate | 1.51 mg/L | 10 mg/L |
| HAA5 | 7.1 ug/L | 60 ug/L |
| Turbidity | 0.088 NTU | 1 NTU |
| Copper | 0.044 mg/L | 1.3 mg/L |
| Barium | 0.058 mg/L | 2 mg/L |
| Bromodichloromethane | 1.23 ug/L | — |
| Bromoform | Not detected ug/L | — |
| Chloroform | 0.85 ug/L | — |
| Dibromochloromethane | 1.91 ug/L | — |
| Lead | Not detected ug/L | 15 ug/L |
| TOC | 0.62–1 mg/L | — |
| PFHxA | 4.4 ng/L | — |
| PFPeA | 4.6 ng/L | — |
| PFBS | 3 ng/L | — |
What this report doesn't tell you
17 of the 27 contaminants a community water system normally reports do not appear anywhere in Dayton, OH's data. Absent is not the same as absent-from-the-water — it means nobody published a number.
+Full detail: PFAS testing, water source, historical monitoring, and the federal violation record
PFAS — EPA UCMR5 (2023–2025)
1 PFAS compound above EPA limits in Dayton, OH
The EPA finalized the first-ever federal drinking-water limits for six PFAS compounds in April 2024. These numbers come straight from EPA's UCMR5 lab dataset — every U.S. system serving more than 3,300 people tested every PFAS sample at an entry point to its distribution system. PFAS not listed below were either tested and not detected, or not yet sampled.
PFOS (Perfluorooctane sulfonic acid)
● Over EPA limit (2.5×)PFHxS (Perfluorohexane sulfonic acid)
● Approaching limit (98%)PFHxA
● Detected (no federal limit)PFPeA
● Detected (no federal limit)PFBS
● Detected (no federal limit)Where your water comes from · EPA SDWIS
Dayton, OH's drinking water comes from ground water under the influence of surface water, drawn from 108 sources.
Source
- DAYTON, CITY OF-OTTAWA P · 51
- DAYTON, CITY OF-MIAMI PL · 33
- DAYTON, CITY OF- OTTAWA PLANT · 10
- DAYTON, CITY OF- MIAMI PLANT · 3
- + 9 more
Treatment
- DAYTON PWS MIAMI PLANT
- DAYTON PWS OTTAWA PLANT
Distribution
Compliance history
Federal Safe Drinking Water Act violation & enforcement records (EPA SDWIS). A violation is a regulatory determination by the state or EPA — separate from the measured levels above.
- Maximum contaminant level exceededHealth-based2 violations on record · most recent Sep 1992resolved
- Treatment technique violationHealth-based1 violation on record · most recent May 2009resolved
Source: EPA SDWIS / ECHO. View the full federal record on EPA ECHO ↗