State distribution
Hardness across indexed ZIPs
Counts describe published ZIP profiles, not a population-weighted statewide sample.
Soft · 0–60 PPM4
Moderately hard · 61–120 PPM2
Hard · 121–180 PPM7
Very hard · 181+ PPM34
State water index
Oklahoma water hardness
Search 108 indexed communities and 148 ZIP profiles, then compare the underlying utility, source, distance, and reporting context.
Median regional evidence
293PPM
Very Hard
Indexed range 7–1700 PPM
- ZIP profiles
- 148
- Cities
- 108
- Matched utilities
- 108
- Counties
- 58
Understanding Oklahoma
Why local comparisons matter here
Oklahoma spans eastern uplands, central red-bed country, western plains, major reservoirs, and several important aquifer systems.
In this index, very hard is the largest category, covering 34 of 47 profiles with hardness data. The state median is 293 PPM, but the full indexed range is 7–1700 PPM.
Evidence coverage
What the current records support
- Hardness estimate
- 32%
- Lead 90th percentile
- 100%
- Copper 90th percentile
- 9%
36
Low-confidence hardness profiles
5
Research-comparison eligible profiles
Reported source water
Utility source mix
- Surface water
- 57
- Groundwater
- 49
- Groundwater influenced by surface water
- 2
Highest medians
Highest eligible city medians
Lowest medians
Lowest eligible city medians
City directory
Explore Oklahoma by city
Search by city or county, then sort by name, hardness, or ZIP coverage.
108 cities · 148 ZIP profiles
108 cities found
Page 1 of 5
Ada
Pontotoc County · 2 ZIPs
305PPM regional
Single regional valueNo active flag
Altus
Jackson County · 2 ZIPs
—
No regional sampleNo active flag
Alva
Woods County · 1 ZIP
—
No regional sampleNo active flag
Apache
Caddo County · 1 ZIP
—
No regional sample1 active record
Ardmore
Carter County · 2 ZIPs
419PPM regional
Single regional valueNo active flag
Arkoma
Le Flore County · 1 ZIP
46PPM regional
Single regional valueNo active flag
Atoka
Atoka County · 1 ZIP
—
No regional sampleNo active flag
Barnsdall
Osage County · 1 ZIP
—
No regional sampleNo active flag
Bartlesville
Washington County · 1 ZIP
—
No regional sampleNo active flag
Beaver
Beaver County · 1 ZIP
293PPM regional
Single regional valueNo active flag
Bethany
Oklahoma County · 1 ZIP
610PPM regional
Single regional valueNo active flag
Blackwell
Kay County · 1 ZIP
—
No regional sampleNo active flag
Broken Arrow
Tulsa County · 2 ZIPs
—
No regional sampleNo active flag
Buffalo
Harper County · 1 ZIP
93PPM regional
Single regional valueNo active flag
Cache
Comanche County · 1 ZIP
—
No regional sampleNo active flag
Carnegie
Caddo County · 1 ZIP
—
No regional sampleNo active flag
Chandler
Lincoln County · 1 ZIP
210PPM regional
Single regional value1 active record
Cherokee
Alfalfa County · 1 ZIP
—
No regional sampleNo active flag
Chickasha
Grady County · 1 ZIP
—
No regional sample1 active record
Claremore
Rogers County · 1 ZIP
—
No regional sampleNo active flag
Clinton
Custer County · 1 ZIP
—
No regional sampleNo active flag
Collinsville
Tulsa County · 1 ZIP
—
No regional sampleNo active flag
Commerce
Ottawa County · 1 ZIP
143PPM regional
Single regional value1 active record
Cushing
Payne County · 1 ZIP
149PPM regional
Single regional valueNo active flag
County comparison
Highest regional-evidence county medians
| County | Median | Range | ZIP profiles |
|---|---|---|---|
| Blaine County | 1700 PPM | 610–1700 | 3 |
| Major County | 1700 PPM | 1700–1700 | 1 |
| Caddo County | 610 PPM | 610–610 | 4 |
| Oklahoma County | 610 PPM | 610–610 | 2 |
| Grady County | 610 PPM | 610–610 | 3 |
| Kingfisher County | 610 PPM | 610–610 | 2 |
| Tillman County | 554 PPM | 554.2–554.2 | 2 |
| Carter County | 419 PPM | 419–419 | 5 |
| Canadian County | 398 PPM | 389–522 | 5 |
| Mcclain County | 364 PPM | 334.5–389 | 4 |
| Garvin County | 305 PPM | 305–305 | 3 |
| Pontotoc County | 305 PPM | 305–305 | 2 |