Skip to content

City water profile

Janesville water quality

Compare local ZIP estimates, evidence quality, associated public systems, and compliance history for Janesville, Wisconsin.

Median indexed hardness

396PPM

3 indexed ZIPs

Range 396–400.5 PPM

State comparison
108 PPM above
State hardness rank
#53 of 479
Matched utilities
3
Active health records
0

City summary

What the indexed records say

Janesville has 3 published ZIP profiles across Rock County. The indexed median is 396 PPM, compared with 288 PPM across Wisconsin.

Among the 479 Wisconsincities with an indexed median, Janesville ranks #53from highest to lowest. Across all 556 state ZIP profiles, available estimates run from 41.3to 467 PPM.

The 396–400.5 PPM range shows how much the available ZIP estimates vary within the city label. At least one estimate is marked low confidence, so observation distance and date deserve extra attention.

Hardness distribution

How local ZIP estimates compare

Soft0 ZIPs
Moderately hard0 ZIPs
Hard0 ZIPs
Very hard3 ZIPs

3 of 3 ZIP profiles have a hardness estimate. Bars count ZIP profiles, not households or laboratory samples.

Evidence quality

Distance, dates, and confidence

Median nearest distance
28.2 miles
Profiles with evidence
3/3

Confidence labels

High: 0Moderate: 1Low: 2

Observation window: Aug 3, 2016 to Aug 8, 2024.

ZIP directory

Water reports in Janesville

Open a ZIP for site-level provenance and measurements.

ZIP code

53545

Very Hard

396 PPM

Nearest site
28.2 mi
Confidence
Low

View full ZIP evidence →

ZIP code

53546

Very Hard

400.5 PPM

Nearest site
20.6 mi
Confidence
Moderate

View full ZIP evidence →

ZIP code

53548

Very Hard

396 PPM

Nearest site
28.8 mi
Confidence
Low

View full ZIP evidence →

Public water systems

Utilities associated with this city

Janesville Water Utility

PWSID WI1540127

Groundwater
System population served
64,415
Last reported
May 29, 2026

The system names this served city; Census place overlap links the city to this ZCTA.

Rockvale Mhp

PWSID WI1540126

Groundwater
System population served
1,200
Last reported
May 29, 2026

The system names this served city; Census place overlap links the city to this ZCTA.

Caravilla Education And Rehab Center

PWSID WI1540111

Groundwater
System population served
298
Last reported
May 29, 2026

The system names this served city; Census place overlap links the city to this ZCTA.

Compliance history

What EPA records show

No active health-based violation appears among the associated systems in the represented EPA reporting quarter. This does not mean every contaminant was tested at every tap.

RecordSystemPeriodStatus
LEAD AND COPPER RULE REVISIONSWI1540111Oct 17, 2024Resolved · health-based
Public NoticeWI1540111Oct 17, 2024Unaddressed
Consumer Confidence RuleWI1540111Jul 1, 2023Resolved
Consumer Confidence RuleWI1540111Jul 1, 2023Resolved
Lead and Copper RuleWI1540111Jan 1, 2022Resolved
Lead and Copper RuleWI1540111Jan 1, 2013Unaddressed
Public NoticeWI1540111Feb 1, 2010Unaddressed
Public NoticeWI1540111Jan 1, 2010Unaddressed

Practical next steps

Move from index to evidence

  1. 1. Open your ZIP. Check distance, dates, confidence, and the associated utility.
  2. 2. Read the current CCR. Confirm source water, detections, limits, ranges, and notices.
  3. 3. Test the tap when needed. Confirm health concerns or treatment sizing with the right method.

Questions people ask

About water in Janesville

Is the water hard?

The indexed city median is 396 PPM. Open the ZIP report to verify the distance and confidence behind that estimate.

Is the tap water safe?

Compliance history is utility-wide and cannot guarantee conditions at every tap. Check current notices and test when address-specific evidence is needed.

Do I need treatment?

Choose treatment only after confirming the problem at the property. A softener targets hardness; contaminant treatment requires a matching, verified performance claim.