Public water system record
Walnut Valley Water District
Serves Diamond Bar, Walnut, Rowland Heights and 2 more places, Los Angeles County, CA · 100,941 people served
Federal records show no health-based violations and no monitoring or reporting issues for Walnut Valley Water District in the last ten years.
System profile
- Health-based violations, last 10 years
- 0
- Resolved
- 0
- Unresolved
- 0
- Any acute record
- No
- Monitoring issues, last 10 years
- 0
Key facts
- Walnut Valley Water District buys its water from Metropolitan Water Dist. of So. Cal. and Three Valleys MWD.
- Record on file since 1994, with 1 health-based violation before October 19, 2016.
- Lead pipe inventory: 0 lead and 0 unknown out of 27,655 service lines.
Check whether Walnut Valley Water District serves your address
Health-based violations
Since October 2016Violation data reflects EPA records through March 2026. For the most current status, visit the EPA ECHO database.
None since October 2016, and no monitoring or reporting violations either.
Full record since 1994
EPA's records for Walnut Valley Water District go back to 1994. Before October 19, 2016 they list 1 health-based violation (1 resolved) and no monitoring or reporting violations.
| Violations that began in | Health-based | Monitoring and reporting |
|---|---|---|
| 1990s | 1 | 0 |
Most recent health-based violation before October 19, 2016: Total Coliform, began September 1994, Resolved.
Show the health-based violation before October 19, 2016
| Contaminant | Start date | Status |
|---|---|---|
|
Total Coliform
Contaminant limit exceeded
|
Sep 1, 1994 | Resolved |
Where the water comes from
Walnut Valley Water District buys its water from Metropolitan Water Dist. of So. Cal. and Three Valleys MWD. It lists no wells or intakes of its own. 3 other community water systems buy water from Walnut Valley Water District.
Buys water from
- Metropolitan Water Dist. of So. Cal. La Verne, CA
- Three Valleys MWD Claremont, CA
Community systems that buy water from it
- GSWC-San Dimas San Dimas, CA
- Suburban Water Systems-Covina Knolls Covina, CA
- Suburban Water Systems-San Jose Covina, CA
Annual water quality report
Walnut Valley Water District must give its customers an annual water quality report (Consumer Confidence Report) by July 1, with the levels its tests found in the previous year.
Systems serving 10,000 or more people must mail or deliver the report to every customer, and from 2027 they must send it twice a year.
Find a posted report with EPA's Consumer Confidence Report search
Testing your own water
To test the water at your tap, or a private well this record does not cover, use a laboratory certified for drinking water by California.
Certified drinking water labs by state EPA guidance for private wells