Is Mason, OH tap water safe?
Data: U.S. EPA · How we read the data · How we check it
Summary
No federal limits exceeded in EPA data for Butler County Water District 2 Public Water System. 2 PFAS were detected below the limits.
2 public water systems serve parts of Mason. The largest, Butler County Water District 2 Public Water System, serves 116,572 people. Your water bill names your system.
Largest system
Butler County Water District 2 Public Water System
116,572 people · Purchased surface water · EPA ID OH0900303
Buys treated water from Hamilton Public Water System, Warren County Water System, Cincinnati Public Water System.
| PFAS | Highest average | Limit |
|---|---|---|
| PFOA Not detected | – | 4 ppt |
| PFOS Not detected | – | 4 ppt |
| PFHxS Detected, below limit | 2.35 ppt | 10 ppt |
| PFNA Not detected | – | 10 ppt |
| HFPO-DA (GenX) Not detected | – | 10 ppt |
ppt = parts per trillion. "Highest average" is the highest average at any of the system's entry points, the way EPA compares results with the limits.
Lead: 3 ppb at the 90th percentile (Nov 2026, and 9 in 10 homes sampled were at or below it) Below action level
Health-based violations since 2016: 0
Full Butler County Water District 2 Public Water System results
Across Ohio, 35 of 331 water systems EPA tested had PFAS above a 2024 federal limit, and 3 systems were above the lead action level in results from the last five years. Ohio results.
Mason homes and lead pipes
Lead service lines and lead solder were allowed until 1986, so homes from before then are the ones to check. How to check your own line.
Housing: Census American Community Survey 2020–2024 5-year estimates for Mason city (tables B25034, B25003). Estimates for small places have a margin of error.
Other water systems serving Mason
How nearby cities compare
| City | PFAS | Lead (90th pct.) |
|---|---|---|
| Middletown 11 mi Butler County Water District 2 Public Water System | None above limits | 3 ppb |
| Fairfield 13 mi Butler County Water District 2 Public Water System | None above limits | 3 ppb |
| Hamilton 14 mi Butler County Water District 2 Public Water System | None above limits | 3 ppb |
| Cincinnati 18 mi Cincinnati Public Water System | Above limit | 2.05 ppb |
| Kettering 25 mi Montgomery County Water Services 1 Public Water System | Above limit | 0 ppb |
| Beavercreek 29 mi Montgomery County Water Services 2 Public Water System | None above limits | 0 ppb |
Mason ZIP codes (1)
- 45040
Questions
Is Mason tap water safe to drink?
Butler County Water District 2 Public Water System has had no health-based violations since 2016. Utility data can't show lead from your own pipes: if your home was built before 1986, test your tap. Your utility's annual Consumer Confidence Report is the official summary.
Who supplies water in Mason, OH?
2 public water systems serve parts of Mason. The largest is Butler County Water District 2 Public Water System (116,572 people). Your water bill names your system. The EPA ID is also on your utility's Consumer Confidence Report.
Does Mason tap water have PFAS?
Butler County Water District 2 Public Water System had 2 PFAS detected at least once in EPA's 2023–2025 testing, all with averages below the federal limits.
Do Mason homes have lead pipes?
Census estimates put 22% of Mason homes as built before 1980 (Ohio: 63%). Lead service lines and lead solder were allowed until 1986, so older homes are more likely to have them. Butler County Water District 2 Public Water System's service line inventory says what your line is made of. The only way to know for your home is to check the line where it enters the house and test your tap.
Source: U.S. EPA drinking water records and PFAS testing (UCMR 5). How we read the data.