Public water system
Napa, City Of
PWSID CA2810003 - Napa County, California
78 PPM
4.5 GPG
Slightly Hard0Soft60120180300+
Slightly Hard (78 PPM)Verified - State Lab Tested
System Details
- Water source
- surface water
- Population served
- 84,804
- Service connections
- 25,376
- Status
- Active
Hardness Evidence
- Reported hardness
- 78 PPM
- Grains per gallon
- 4.5 GPG
- Data source
- California treated-water report
- Source year
- 2024
- Raw/source estimate
- 81 PPM
Linked City Reports
Served ZIP Codes
| ZIP | Location | ZIP average |
|---|---|---|
| 94508 | Angwin, CA | Slightly Hard (79 PPM) |
| 94515 | Calistoga, CA | Slightly Hard (86 PPM) |
| 94558 | Spanish Flat, CA | Slightly Hard (82 PPM) |
| 94559 | Napa, CA | Slightly Hard (78 PPM) |
| 94567 | Pope Valley, CA | Slightly Hard (78 PPM) |
| 94574 | Saint Helena, CA | Slightly Hard (78 PPM) |
| 94576 | Deer Park, CA | Slightly Hard (78 PPM) |
| 94599 | Yountville, CA | Slightly Hard (78 PPM) |
How to Use This System Page
A public water system can serve multiple ZIP codes and cities. Use this page to inspect the source behind the hardness reading, then open the linked ZIP or city page for the local rollup.
If you are sizing treatment equipment, confirm your actual tap hardness with a home test or lab test before buying.