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City water profile

Diagonal water quality

Compare local ZIP estimates, evidence quality, associated public systems, and compliance history for Diagonal, Iowa.

Median indexed hardness

200PPM

One indexed ZIP

Range 200–200 PPM

State comparison
81 PPM below
State hardness rank
#667 of 683
Matched utilities
1
Active health records
0

City summary

What the indexed records say

Diagonal has 1 published ZIP profile across Ringgold County. The indexed median is 200 PPM, compared with 281 PPM across Iowa.

Among the 683 Iowacities with an indexed median, Diagonal ranks #667from highest to lowest. Across all 723 state ZIP profiles, available estimates run from 182to 834 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 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
25.1 miles
Profiles with evidence
1/1

Confidence labels

High: 0Moderate: 0Low: 1

Observation window: Jan 11, 2016 to Jul 28, 2025.

ZIP directory

Water reports in Diagonal

Open a ZIP for site-level provenance and measurements.

ZIP code

50845

Very Hard

200 PPM

Nearest site
25.1 mi
Confidence
Low

View full ZIP evidence →

Public water systems

Utilities associated with this city

Diagonal Water Department

PWSID IA8018040

Surface water
System population served
338
Last reported
Jun 17, 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
TTHMIA8018040Nov 1, 2025Resolved
Total Haloacetic Acids (HAA5)IA8018040Nov 1, 2025Resolved
Lead and Copper RuleIA8018040Jun 1, 2025Unaddressed
Public NoticeIA8018040Mar 21, 2025Unaddressed
Public NoticeIA8018040Oct 21, 2024Unaddressed
NitriteIA8018040Oct 1, 2024Resolved
Revised Total Coliform RuleIA8018040Oct 1, 2024Resolved
NitriteIA8018040Apr 1, 2024Resolved
NitriteIA8018040Jan 1, 2024Resolved
Revised Total Coliform RuleIA8018040Apr 1, 2023Resolved

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 Diagonal

Is the water hard?

The indexed city median is 200 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.