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City water profile

Merrillville water quality

Compare local ZIP estimates, evidence quality, associated public systems, and compliance history for Merrillville, Indiana.

Median indexed hardness

265PPM

One indexed ZIP

Range 265–265 PPM

State comparison
48 PPM below
State hardness rank
#327 of 386
Matched utilities
3
Active health records
0

City summary

What the indexed records say

Merrillville has 1 published ZIP profile across Lake County. The indexed median is 265 PPM, compared with 313 PPM across Indiana.

Among the 386 Indianacities with an indexed median, Merrillville ranks #327from highest to lowest. Across all 472 state ZIP profiles, available estimates run from 132to 371 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
9.3 miles
Profiles with evidence
1/1

Confidence labels

High: 0Moderate: 1Low: 0

Observation window: Apr 26, 2016 to May 13, 2026.

ZIP directory

Water reports in Merrillville

Open a ZIP for site-level provenance and measurements.

ZIP code

46410

Very Hard

265 PPM

Nearest site
9.3 mi
Confidence
Moderate

View full ZIP evidence →

Public water systems

Utilities associated with this city

Indiana American Water - Northwest

PWSID IN5245015

Surface water
System population served
210,510
Last reported
Jun 30, 2026

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

Crossings Mobile Home Park

PWSID IN5245014

Groundwater
System population served
100
Last reported
Jun 30, 2026

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

Rockwell Shores Apartments

PWSID IN5245002

Groundwater
System population served
45
Last reported
Jun 30, 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
Revised Total Coliform RuleIN5245014Aug 1, 2025Resolved · health-based
Revised Total Coliform RuleIN5245002Apr 1, 2025Resolved
Gross Alpha, Excl. Radon and UIN5245014Jul 1, 2024Resolved
Radium-226IN5245014Jul 1, 2024Resolved
Radium-228IN5245014Jul 1, 2024Resolved
Revised Total Coliform RuleIN5245014Apr 11, 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 Merrillville

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.