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City water profile

Blackwell water quality

Compare local ZIP estimates, evidence quality, associated public systems, and compliance history for Blackwell, Oklahoma.

Median indexed hardness

115PPM

One indexed ZIP

Range 114.5–114.5 PPM

State comparison
111 PPM below
State hardness rank
#92 of 108
Matched utilities
1
Active health records
0

City summary

What the indexed records say

Blackwell has 1 published ZIP profile across Kay County. The indexed median is 115 PPM, compared with 226 PPM across Oklahoma.

Among the 108 Oklahomacities with an indexed median, Blackwell ranks #92from highest to lowest. Across all 148 state ZIP profiles, available estimates run from 7to 610 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

Soft0 ZIPs
Moderately hard1 ZIP
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
55.3 miles
Profiles with evidence
1/1

Confidence labels

High: 0Moderate: 0Low: 1

Observation window: Feb 17, 2016 to May 19, 2026.

ZIP directory

Water reports in Blackwell

Open a ZIP for site-level provenance and measurements.

ZIP code

74631

Moderately Hard

114.5 PPM

Nearest site
55.3 mi
Confidence
Low

View full ZIP evidence →

Public water systems

Utilities associated with this city

Blackwell Municipal Authority

PWSID OK1021101

Surface water
System population served
7,668
Last reported
May 13, 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
Interim Enhanced Surface Water Treatment RuleOK1021101Jul 1, 2025Resolved · health-based
Interim Enhanced Surface Water Treatment RuleOK1021101Jun 1, 2025Resolved · health-based
Interim Enhanced Surface Water Treatment RuleOK1021101May 1, 2025Resolved
Chlorine dioxideOK1021101May 1, 2025Resolved
TTHMOK1021101Apr 1, 2025Resolved
Interim Enhanced Surface Water Treatment RuleOK1021101Jan 1, 2025Resolved · health-based
Interim Enhanced Surface Water Treatment RuleOK1021101Jun 1, 2024Resolved · health-based
Interim Enhanced Surface Water Treatment RuleOK1021101Mar 1, 2024Resolved · health-based
Interim Enhanced Surface Water Treatment RuleOK1021101Mar 1, 2024Resolved · health-based
TTHMOK1021101Jan 1, 2023Resolved · 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 Blackwell

Is the water hard?

The indexed city median is 115 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.