Janesville
Janesville, WI water profile — supply sources, drought status, wastewater reuse, and the key water issues facing the city.
janesville water utility
groundwater (wells) · local government · PWSID WI1540127
Below EPA's 15 ppb lead action level at last testing.
Source: EPA Safe Drinking Water Information System (SDWIS) · 2026 Q1
Janesville, WI is a small but growing city, with a population near 64,123 and the 10th-largest community in Wisconsin. Like much of Wisconsin, Janesville draws its water primarily from Great Lakes, Wisconsin River, and aquifers.
Janesville's water outlook is shaped most by aging infrastructure — the issue that dominates planning across Wisconsin. Great Lakes access is abundant, but PFAS and nitrate contamination affect many private and municipal wells.
Janesville sits in a state that reuses roughly 3% of treated wastewater (minimal programs) and currently experiences abnormally dry to moderate drought.
For the bigger picture, see the Wisconsin state water profile and the related issues below.
Rock County water quality
Source: EPA SDWIS · 2026 Q1
At a glance
- Population ~64,123 (10th-largest in Wisconsin)
- Primary sources: Great Lakes, Wisconsin River, and aquifers
- Drought: abnormally dry to moderate conditions
- State reuse rate: ~3% of wastewater
Statewide drought history
% of Wisconsin in severe+ drought (Moderate (D1) now).
Source: U.S. Drought Monitor
Common questions
Is tap water safe in Janesville?
Janesville's largest water system, JANESVILLE WATER UTILITY, serves about 64,415 people. EPA records show 0 health-based violation(s) since 2016 and a most-recent 90th-percentile lead level of 10 ppb (EPA action level is 15 ppb). Always check your own provider's annual Consumer Confidence Report.
Where does Janesville get its water?
JANESVILLE WATER UTILITY draws primarily from groundwater (wells), part of Wisconsin's supply from Great Lakes, Wisconsin River, aquifers.
Related water issues
Aging Infrastructure
Much of America's water infrastructure is decades past its design life, leaking trillions of gallons a year and demanding hundreds of billions in reinvestment.
ExplorePFAS Contamination
Per- and polyfluoroalkyl substances persist in water supplies for decades. New federal limits are forcing utilities nationwide to invest in advanced treatment.
Explore