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City water profile

Chicago water quality

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

Median indexed hardness

247PPM

57 indexed ZIPs

Range 243–265 PPM

State comparison
38 PPM below
State hardness rank
#735 of 913
Matched utilities
1
Active health records
0

City summary

What the indexed records say

Chicago has 57 published ZIP profiles across Cook County. The indexed median is 247 PPM, compared with 285 PPM across Illinois.

Among the 913 Illinoiscities with an indexed median, Chicago ranks #735from highest to lowest. Across all 1,065 state ZIP profiles, available estimates run from 115to 408 PPM.

The 243–265 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 hard57 ZIPs

57 of 57 ZIP profiles have a hardness estimate. Bars count ZIP profiles, not households or laboratory samples.

Evidence quality

Distance, dates, and confidence

Median nearest distance
13.6 miles
Profiles with evidence
57/57

Confidence labels

High: 0Moderate: 57Low: 0

Observation window: Apr 12, 2016 to May 13, 2026.

ZIP directory

Water reports in Chicago

Open a ZIP for site-level provenance and measurements.

ZIP code

60018

Very Hard

251 PPM

Nearest site
22.2 mi
Confidence
Moderate

View full ZIP evidence →

ZIP code

60601

Very Hard

243 PPM

Nearest site
13.5 mi
Confidence
Moderate

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ZIP code

60602

Very Hard

243 PPM

Nearest site
13.4 mi
Confidence
Moderate

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ZIP code

60603

Very Hard

243 PPM

Nearest site
13.2 mi
Confidence
Moderate

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ZIP code

60604

Very Hard

243 PPM

Nearest site
13.1 mi
Confidence
Moderate

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ZIP code

60605

Very Hard

245 PPM

Nearest site
12.2 mi
Confidence
Moderate

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ZIP code

60606

Very Hard

243 PPM

Nearest site
13.4 mi
Confidence
Moderate

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ZIP code

60607

Very Hard

245 PPM

Nearest site
13.2 mi
Confidence
Moderate

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ZIP code

60608

Very Hard

245 PPM

Nearest site
11.7 mi
Confidence
Moderate

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ZIP code

60609

Very Hard

245 PPM

Nearest site
9.3 mi
Confidence
Moderate

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ZIP code

60610

Very Hard

247 PPM

Nearest site
14.9 mi
Confidence
Moderate

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ZIP code

60611

Very Hard

245 PPM

Nearest site
14.1 mi
Confidence
Moderate

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ZIP code

60612

Very Hard

247 PPM

Nearest site
14.2 mi
Confidence
Moderate

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ZIP code

60613

Very Hard

251 PPM

Nearest site
18.6 mi
Confidence
Moderate

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ZIP code

60614

Very Hard

247 PPM

Nearest site
16.3 mi
Confidence
Moderate

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ZIP code

60615

Very Hard

251 PPM

Nearest site
7.7 mi
Confidence
Moderate

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ZIP code

60616

Very Hard

245 PPM

Nearest site
10.8 mi
Confidence
Moderate

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ZIP code

60617

Very Hard

260 PPM

Nearest site
1.6 mi
Confidence
Moderate

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ZIP code

60618

Very Hard

247 PPM

Nearest site
18.8 mi
Confidence
Moderate

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ZIP code

60619

Very Hard

251 PPM

Nearest site
3.8 mi
Confidence
Moderate

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ZIP code

60620

Very Hard

251 PPM

Nearest site
5.2 mi
Confidence
Moderate

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ZIP code

60621

Very Hard

251 PPM

Nearest site
6.6 mi
Confidence
Moderate

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ZIP code

60622

Very Hard

247 PPM

Nearest site
15.5 mi
Confidence
Moderate

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ZIP code

60623

Very Hard

243 PPM

Nearest site
12.9 mi
Confidence
Moderate

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ZIP code

60624

Very Hard

247 PPM

Nearest site
15.1 mi
Confidence
Moderate

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ZIP code

60625

Very Hard

251 PPM

Nearest site
20.4 mi
Confidence
Moderate

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ZIP code

60626

Very Hard

251 PPM

Nearest site
22.3 mi
Confidence
Moderate

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ZIP code

60628

Very Hard

255 PPM

Nearest site
2.2 mi
Confidence
Moderate

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ZIP code

60629

Very Hard

247 PPM

Nearest site
9.1 mi
Confidence
Moderate

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ZIP code

60630

Very Hard

251 PPM

Nearest site
21.4 mi
Confidence
Moderate

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ZIP code

60631

Very Hard

251 PPM

Nearest site
24.2 mi
Confidence
Moderate

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ZIP code

60632

Very Hard

245 PPM

Nearest site
10.8 mi
Confidence
Moderate

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ZIP code

60633

Very Hard

265 PPM

Nearest site
1.7 mi
Confidence
Moderate

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ZIP code

60634

Very Hard

251 PPM

Nearest site
21.2 mi
Confidence
Moderate

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ZIP code

60636

Very Hard

247 PPM

Nearest site
7.5 mi
Confidence
Moderate

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ZIP code

60637

Very Hard

251 PPM

Nearest site
6.3 mi
Confidence
Moderate

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ZIP code

60638

Very Hard

245 PPM

Nearest site
11.9 mi
Confidence
Moderate

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ZIP code

60639

Very Hard

247 PPM

Nearest site
18.3 mi
Confidence
Moderate

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ZIP code

60640

Very Hard

251 PPM

Nearest site
19.8 mi
Confidence
Moderate

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ZIP code

60641

Very Hard

251 PPM

Nearest site
19.6 mi
Confidence
Moderate

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ZIP code

60642

Very Hard

247 PPM

Nearest site
15.1 mi
Confidence
Moderate

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ZIP code

60643

Very Hard

251 PPM

Nearest site
4.6 mi
Confidence
Moderate

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ZIP code

60644

Very Hard

247 PPM

Nearest site
16 mi
Confidence
Moderate

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ZIP code

60645

Very Hard

251 PPM

Nearest site
22.6 mi
Confidence
Moderate

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ZIP code

60646

Very Hard

251 PPM

Nearest site
22.9 mi
Confidence
Moderate

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ZIP code

60647

Very Hard

247 PPM

Nearest site
17.1 mi
Confidence
Moderate

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ZIP code

60649

Very Hard

251 PPM

Nearest site
4.6 mi
Confidence
Moderate

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ZIP code

60651

Very Hard

247 PPM

Nearest site
16.8 mi
Confidence
Moderate

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ZIP code

60652

Very Hard

247 PPM

Nearest site
8.1 mi
Confidence
Moderate

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ZIP code

60653

Very Hard

245 PPM

Nearest site
8.9 mi
Confidence
Moderate

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ZIP code

60654

Very Hard

247 PPM

Nearest site
14.1 mi
Confidence
Moderate

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ZIP code

60655

Very Hard

251 PPM

Nearest site
6.6 mi
Confidence
Moderate

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ZIP code

60656

Very Hard

251 PPM

Nearest site
23.4 mi
Confidence
Moderate

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ZIP code

60657

Very Hard

247 PPM

Nearest site
17.5 mi
Confidence
Moderate

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ZIP code

60659

Very Hard

251 PPM

Nearest site
21.6 mi
Confidence
Moderate

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ZIP code

60660

Very Hard

251 PPM

Nearest site
21.1 mi
Confidence
Moderate

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ZIP code

60661

Very Hard

247 PPM

Nearest site
13.6 mi
Confidence
Moderate

View full ZIP evidence →

Public water systems

Utilities associated with this city

Chicago

PWSID IL0316000

Surface water
System population served
2,721,308
Last reported
May 27, 2026

A municipal system, in-state city, and served county all agree with this Census 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 REVISIONSIL0316000Jul 2, 2025Resolved
Interim Enhanced Surface Water Treatment RuleIL0316000May 1, 2025Resolved
Interim Enhanced Surface Water Treatment RuleIL0316000Apr 1, 2025Resolved
DinosebIL0316000Jan 1, 2025Archived
CARBON, TOTALIL0316000Jul 1, 2024Resolved
CARBON, TOTALIL0316000Jul 1, 2024Resolved
CARBON, TOTALIL0316000Jul 1, 2024Resolved
CARBON, TOTALIL0316000Jul 1, 2024Resolved
Lead and Copper RuleIL0316000Dec 30, 2021Resolved
Consumer Confidence RuleIL0316000Jul 1, 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 Chicago

Is the water hard?

The indexed city median is 247 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.