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City water profile

Dupo water quality

Compare local ZIP estimates, evidence quality, associated public systems, and compliance history for Dupo, Illinois.

Median indexed hardness

269PPM

2 indexed ZIPs

Range 268.5–268.5 PPM

State comparison
16 PPM below
State hardness rank
#587 of 913
Matched utilities
2
Active health records
0

City summary

What the indexed records say

Dupo has 2 published ZIP profiles across St. Clair County. The indexed median is 269 PPM, compared with 285 PPM across Illinois.

Among the 913 Illinoiscities with an indexed median, Dupo ranks #587from highest to lowest. Across all 1,065 state ZIP profiles, available estimates run from 115to 408 PPM.

The 268.5–268.5 PPM range shows how much the available ZIP estimates vary within the city label.

Hardness distribution

How local ZIP estimates compare

Soft0 ZIPs
Moderately hard0 ZIPs
Hard0 ZIPs
Very hard2 ZIPs

2 of 2 ZIP profiles have a hardness estimate. Bars count ZIP profiles, not households or laboratory samples.

Evidence quality

Distance, dates, and confidence

Median nearest distance
13.7 miles
Profiles with evidence
2/2

Confidence labels

High: 0Moderate: 2Low: 0

Observation window: Jun 1, 2016 to Jul 16, 2024.

ZIP directory

Water reports in Dupo

Open a ZIP for site-level provenance and measurements.

ZIP code

62239

Very Hard

268.5 PPM

Nearest site
11.8 mi
Confidence
Moderate

View full ZIP evidence →

ZIP code

62240

Very Hard

268.5 PPM

Nearest site
13.7 mi
Confidence
Moderate

View full ZIP evidence →

Public water systems

Utilities associated with this city

Dupo

PWSID IL1630350

Groundwater
System population served
4,684
Last reported
May 27, 2026

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

Ildu Lepere Mhp, Llc

PWSID IL1635080

Surface water
System population served
250
Last reported
May 27, 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
TTHMIL1635080Oct 1, 2025Archived
Total Haloacetic Acids (HAA5)IL1635080Oct 1, 2025Archived
Lead and Copper RuleIL1635080Oct 1, 2025Unaddressed
Consumer Confidence RuleIL1630350Jul 1, 2024Resolved
Lead and Copper RuleIL1635080Oct 1, 2022Resolved
Lead and Copper RuleIL1635080Apr 1, 2021Resolved
Public NoticeIL1635080Mar 12, 2021Unaddressed
Public NoticeIL1635080Feb 11, 2021Resolved
Public NoticeIL1635080Feb 11, 2021Resolved

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 Dupo

Is the water hard?

The indexed city median is 269 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.