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City water profile

Markham water quality

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

Median indexed hardness

265PPM

One indexed ZIP

Range 265–265 PPM

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

City summary

What the indexed records say

Markham has 1 published ZIP profile across Cook County. The indexed median is 265 PPM, compared with 285 PPM across Illinois.

Among the 913 Illinoiscities with an indexed median, Markham ranks #600from highest to lowest. Across all 1,065 state ZIP profiles, available estimates run from 115to 408 PPM.

Because only one ZIP is represented, the city median and range are the same local estimate. It should not be read as multiple independent samples across the community.

Hardness distribution

How local ZIP estimates compare

Soft0 ZIPs
Moderately hard0 ZIPs
Hard0 ZIPs
Very hard1 ZIP

1 of 1 ZIP profiles have a hardness estimate. Bars count ZIP profiles, not households or laboratory samples.

Evidence quality

Distance, dates, and confidence

Median nearest distance
8.4 miles
Profiles with evidence
1/1

Confidence labels

High: 0Moderate: 1Low: 0

Observation window: Apr 22, 2016 to May 13, 2026.

ZIP directory

Water reports in Markham

Open a ZIP for site-level provenance and measurements.

ZIP code

60428

Very Hard

265 PPM

Nearest site
8.4 mi
Confidence
Moderate

View full ZIP evidence →

Public water systems

Utilities associated with this city

Markham

PWSID IL0311770

Surface water
System population served
12,500
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
LEAD AND COPPER RULE REVISIONSIL0311770Jul 2, 2025Unaddressed
Consumer Confidence RuleIL0311770Jul 1, 2025Unaddressed
TTHMIL0311770Jul 1, 2025Resolved
Consumer Confidence RuleIL0311770Jul 1, 2023Resolved
Public NoticeIL0311770Jun 15, 2023Resolved
Public NoticeIL0311770Jun 15, 2023Resolved
Revised Total Coliform RuleIL0311770May 1, 2022Resolved
ChlorineIL0311770Apr 1, 2022Resolved

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 Markham

Is the water hard?

The indexed city median is 265 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.