Is Mason City, IA 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 Mason City Water Department.
Mason City Water Department supplies Mason City (27,338 people).
Water system
Mason City Water Department
27,338 people · Groundwater · EPA ID IA1750048
| PFAS | Highest average | Limit |
|---|---|---|
| PFOA Not detected | – | 4 ppt |
| PFOS Not detected | – | 4 ppt |
| PFHxS Not detected | – | 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: 2.9 ppb at the 90th percentile (Dec 2023, and 9 in 10 homes sampled were at or below it) Below action level
Health-based violations since 2016: 0
Across Iowa, 1 of 151 water systems EPA tested had PFAS above a 2024 federal limit, and 4 systems were above the lead action level in results from the last five years. Iowa results.
Mason City homes and lead pipes
Lead service lines and lead solder were allowed until 1986, so homes from before then are the ones to check. Renting? Ask your landlord what the service line is made of, because it's their pipe to replace. How to check your own line.
Housing: Census American Community Survey 2020–2024 5-year estimates for Mason City city (tables B25034, B25003). Estimates for small places have a margin of error.
How nearby cities compare
| City | PFAS | Lead (90th pct.) |
|---|---|---|
| Cedar Falls 57 mi Cedar Falls Municipal Water Utilities | None above limits | 1.4 ppb |
| Waterloo 62 mi Waterloo Water Works | None above limits | 1.8 ppb |
| Marshalltown 78 mi Marshalltown Water Works | None above limits | 2 ppb |
| Ames 80 mi Ames Water Treatment Plant | None above limits | 0 ppb |
| Ankeny 100 mi City of Ankeny | None above limits | 0 ppb |
| Johnston 104 mi Johnston Municipal Water Supply | None above limits | 0 ppb |
Mason City ZIP codes (1)
- 50401
Questions
Is Mason City tap water safe to drink?
Mason City Water Department 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 City, IA?
Mason City Water Department, which serves 27,338 people.
Does Mason City tap water have PFAS?
None detected above EPA's reporting limits. Mason City Water Department had no PFAS detected in EPA's 2023–2025 testing. "Not detected" means below the reporting limit (about 2 to 20 ppt), not proven zero.
Do Mason City homes have lead pipes?
Census estimates put 78% of Mason City homes as built before 1980 (Iowa: 62%). Lead service lines and lead solder were allowed until 1986, so older homes are more likely to have them. Mason City Water Department'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.