State distribution
Hardness across indexed ZIPs
Counts describe published ZIP profiles, not a population-weighted statewide sample.
Soft · 0–60 PPM10
Moderately hard · 61–120 PPM11
Hard · 121–180 PPM19
Very hard · 181+ PPM108
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 indexed hardness
226PPM
Very Hard
Indexed range 7–610 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 108 of 148 profiles with hardness data. The state median is 226 PPM, but the full indexed range is 7–610 PPM.
Evidence coverage
What the current records support
- Hardness estimate
- 100%
- Lead 90th percentile
- 100%
- Copper 90th percentile
- 9%
77
Low-confidence hardness profiles
77
Nearest site more than 25 miles away
Reported source water
Utility source mix
- Surface water
- 57
- Groundwater
- 49
- Groundwater influenced by surface water
- 2
Highest medians
Hardest indexed cities
- 1. Carnegie610 PPM
- 2. Hinton610 PPM
- 3. Weatherford610 PPM
- 4. Altus561 PPM
- 5. Hobart522 PPM
Lowest medians
Softest indexed cities
- 1. Thackerville7 PPM
- 2. Sulphur7 PPM
- 3. Wilson10 PPM
- 4. Lone Grove10 PPM
- 5. Ada36 PPM
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
36PPM
Range 9.5–61.8No active flag
Altus
Jackson County · 2 ZIPs
561PPM
Single indexed valueNo active flag
Alva
Woods County · 1 ZIP
216PPM
Single indexed valueNo active flag
Apache
Caddo County · 1 ZIP
487PPM
Single indexed value1 active record
Ardmore
Carter County · 2 ZIPs
104PPM
Range 101.5–107No active flag
Arkoma
Le Flore County · 1 ZIP
50PPM
Single indexed valueNo active flag
Atoka
Atoka County · 1 ZIP
275PPM
Single indexed valueNo active flag
Barnsdall
Osage County · 1 ZIP
274PPM
Single indexed valueNo active flag
Bartlesville
Washington County · 1 ZIP
137PPM
Single indexed valueNo active flag
Beaver
Beaver County · 1 ZIP
217PPM
Single indexed valueNo active flag
Bethany
Oklahoma County · 1 ZIP
380PPM
Single indexed valueNo active flag
Blackwell
Kay County · 1 ZIP
115PPM
Single indexed valueNo active flag
Broken Arrow
Tulsa County · 2 ZIPs
137PPM
Single indexed valueNo active flag
Buffalo
Harper County · 1 ZIP
217PPM
Single indexed valueNo active flag
Cache
Comanche County · 1 ZIP
298PPM
Single indexed valueNo active flag
Carnegie
Caddo County · 1 ZIP
610PPM
Single indexed valueNo active flag
Chandler
Lincoln County · 1 ZIP
380PPM
Single indexed value1 active record
Cherokee
Alfalfa County · 1 ZIP
243PPM
Single indexed valueNo active flag
Chickasha
Grady County · 1 ZIP
380PPM
Single indexed value1 active record
Claremore
Rogers County · 1 ZIP
144PPM
Single indexed valueNo active flag
Clinton
Custer County · 1 ZIP
398PPM
Single indexed valueNo active flag
Collinsville
Tulsa County · 1 ZIP
137PPM
Single indexed valueNo active flag
Commerce
Ottawa County · 1 ZIP
180PPM
Single indexed value1 active record
Cushing
Payne County · 1 ZIP
305PPM
Single indexed valueNo active flag
County comparison
Highest indexed county medians
| County | Median | Range | ZIP profiles |
|---|---|---|---|
| Jackson County | 561 PPM | 560.5–560.5 | 2 |
| Caddo County | 549 PPM | 364–610 | 4 |
| Kiowa County | 522 PPM | 522–522 | 1 |
| Blaine County | 399 PPM | 321–487 | 3 |
| Custer County | 399 PPM | 398–610 | 3 |
| Major County | 399 PPM | 398.5–398.5 | 1 |
| Canadian County | 380 PPM | 380–380 | 5 |
| Grady County | 380 PPM | 364–487 | 3 |
| Logan County | 380 PPM | 380–380 | 1 |
| Noble County | 380 PPM | 380–380 | 1 |
| Garfield County | 380 PPM | 380–389 | 3 |
| Pottawatomie County | 380 PPM | 380–380 | 2 |