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City water profile

Lewistown water quality

Compare local ZIP estimates, evidence quality, associated public systems, and compliance history for Lewistown, Montana.

Median indexed hardness

0PPM

One indexed ZIP

Range 0.2–0.2 PPM

State comparison
122 PPM below
State hardness rank
#117 of 117
Matched utilities
5
Active health records
0

City summary

What the indexed records say

Lewistown has 1 published ZIP profile across Fergus County. The indexed median is 0 PPM, compared with 122 PPM across Montana.

Among the 117 Montanacities with an indexed median, Lewistown ranks #117from highest to lowest. Across all 145 state ZIP profiles, available estimates run from 0.2to 799.5 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. At least one estimate is marked low confidence, so observation distance and date deserve extra attention.

Hardness distribution

How local ZIP estimates compare

Soft1 ZIP
Moderately hard0 ZIPs
Hard0 ZIPs
Very hard0 ZIPs

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
68.5 miles
Profiles with evidence
1/1

Confidence labels

High: 0Moderate: 0Low: 1

Observation window: Mar 4, 2017 to Feb 26, 2025.

ZIP directory

Water reports in Lewistown

Open a ZIP for site-level provenance and measurements.

ZIP code

59457

Soft

0.2 PPM

Nearest site
68.5 mi
Confidence
Low

View full ZIP evidence →

Public water systems

Utilities associated with this city

Lewistown City Of

PWSID MT0000271

Groundwater
System population served
5,923
Last reported
Jun 29, 2026

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

Mountain Acres Mb Hm Pk

PWSID MT0003809

Groundwater
System population served
320
Last reported
Jun 29, 2026

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

King Ranch Colony

PWSID MT0000432

Groundwater
System population served
56
Last reported
Jun 29, 2026

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

Deerfield Hutterite Colony

PWSID MT0000431

Groundwater
System population served
51
Last reported
Jun 29, 2026

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

Spring Creek Colony Lewistown

PWSID MT0000433

Groundwater
System population served
48
Last reported
Jun 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
Revised Total Coliform RuleMT0000432Feb 1, 2026Resolved
Nitrate-NitriteMT0000432Jan 1, 2026Archived · health-based
Nitrate-NitriteMT0000432Oct 1, 2025Archived · health-based
Consumer Confidence RuleMT0000271Jul 1, 2025Resolved
Nitrate-NitriteMT0000432Jul 1, 2025Archived · health-based
Consumer Confidence RuleMT0000431Jul 1, 2025Resolved
Nitrate-NitriteMT0000432Apr 1, 2025Archived · health-based
TTHMMT0003809Jan 1, 2025Archived
Total Haloacetic Acids (HAA5)MT0003809Jan 1, 2025Archived
Nitrate-NitriteMT0000432Jan 1, 2025Archived · health-based

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 Lewistown

Is the water hard?

The indexed city median is 0 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.