Water Hardness in Missouri
Is Missouri Water Hard or Soft?
Missouri water is hard on average at 219 PPM (12.8 GPG). Local readings can vary by utility, aquifer, treatment plant, and private well use.
76% of covered ZIPs use treated-water records or USGS monitoring, so the state report has relatively strong source support.
How to read the Missouri results
State pages are screening and comparison hubs. They summarize ZIP, city, and water-system patterns so you can find the local page that best matches your home or utility.
Use the source coverage below to judge how much local confirmation a specific city or ZIP needs. The methodology page explains the source hierarchy, weighting, and limitations.
Data Source Coverage
ZIP-level source mix for Missouri; higher direct and USGS coverage means less reliance on regional estimates.
In Missouri, 35% of ZIPs use verified treated-water records, 41% use high-confidence USGS monitoring, and 24% use estimates that should be confirmed locally for treatment decisions.
What the Data Shows in Missouri
Hard water is common but not universal in Missouri: 59% of classified ZIPs are hard or very hard.
Missouri uses a mixed data profile across treated-water records, USGS monitoring, and estimated fallback values.
Use the city table below to compare local results. For estimated locations or unusually high readings, confirm with your utility or a home hardness test before sizing treatment equipment.
ZIP Hardness Distribution
Treatment Takeaway
For many homes in Missouri, hardness is high enough that scale buildup, fixture spotting, and appliance wear are realistic concerns. A local test is the best starting point before sizing a softener.
How to Use This Data
The source coverage is relatively strong in Missouri, so these pages are useful for comparing local patterns before confirming your home's exact hardness.
Source-Backed Water Systems in Missouri
Large systems with treated-water reports or USGS monitoring behind the state rollup.
| Water system | Hardness | Source label | Population |
|---|---|---|---|
| Liberty Pws MO1010466 - Clay County | 260 PPM Very Hard | Annual Water Quality Report Verified - Annual Water Quality Report | 30,800 |
| Gladstone Pws MO1010307 - Clay County | 260 PPM Very Hard | Annual Water Quality Report Verified - Annual Water Quality Report | 27,000 |
| Mo American Platte County MO1010625 - Platte County | 260 PPM Very Hard | Annual Water Quality Report Verified - Annual Water Quality Report | 16,645 |
| Kearney Pws MO1010416 - Clay County | 260 PPM Very Hard | Annual Water Quality Report Verified - Annual Water Quality Report | 11,500 |
| Excelsior Springs Pws MO1010261 - Clay County | 260 PPM Very Hard | Annual Water Quality Report Verified - Annual Water Quality Report | 11,084 |
| Smithville Pws MO1010748 - Clay County | 260 PPM Very Hard | Annual Water Quality Report Verified - Annual Water Quality Report | 10,885 |
| Platte County Cons Pwsd 1 MO1024479 - Platte County | 260 PPM Very Hard | Annual Water Quality Report Verified - Annual Water Quality Report | 6,900 |
| Springdale Lake Estates MO1048081 - Cass County | 260 PPM Very Hard | Annual Water Quality Report Verified - Annual Water Quality Report | 1,500 |
Useful Missouri City Pages
Shortcuts to city pages backed by more ZIP-code or water-system data.
Cities With More Local Data
Prioritize cities with multiple ZIPs and systems, then use the local source badges to compare high-confidence USGS readings against estimated areas.
Top 10 Hardest Water Cities
| # | City | Hardness |
|---|---|---|
| 1 | Desloge | Very Hard (653 PPM) |
| 2 | Warrenton | Very Hard (509 PPM) |
| 3 | Wright City | Very Hard (418 PPM) |
| 4 | Warrensburg | Very Hard (319 PPM) |
| 5 | Knob Noster | Very Hard (318 PPM) |
| 6 | Wappapello | Very Hard (317 PPM) |
| 7 | Elsberry | Very Hard (307 PPM) |
| 8 | Rolla | Very Hard (305 PPM) |
| 9 | Roach | Very Hard (304 PPM) |
| 10 | Osage Beach | Very Hard (301 PPM) |
Top 10 Softest Water Cities
| # | City | Hardness |
|---|---|---|
| 1 | Augusta | Moderately Hard (120 PPM) |
| 2 | Chesterfield | Moderately Hard (120 PPM) |
| 3 | Columbia | Moderately Hard (120 PPM) |
| 4 | Defiance | Moderately Hard (120 PPM) |
| 5 | Fenton | Moderately Hard (120 PPM) |
| 6 | Florissant | Moderately Hard (120 PPM) |
| 7 | Jefferson City | Moderately Hard (120 PPM) |
| 8 | Lake Saint Louis | Moderately Hard (120 PPM) |
| 9 | O Fallon | Moderately Hard (120 PPM) |
| 10 | Saint Charles | Moderately Hard (120 PPM) |
All Cities in Missouri
City pages marked Estimated use fallback values and should be confirmed with local testing or utility data.