Does Diamond Bar, CA tap water have any EPA-reported violations?

As of October 2026, EPA SDWIS records show 3 violation(s) across the community water systems serving Diamond Bar, of which 0 are classified by the EPA as health-based. Most older violations have returned to compliance; see the per-system list.

Where does Diamond Bar, CA tap water come from?

Diamond Bar is served by 2 active community water system(s). Their primary sources, per EPA records, are: surface water.

CA / Diamond Bar

CA · Tap water records

Diamond Bar tap water, in plain English

Here is what the EPA's own data shows about tap water in Diamond Bar. According to EPA SDWIS data retrieved October 2026, Diamond Bar is served by 2 active community water systems, together reported to serve about 232 people.

As of October 2026, EPA records show 3 violations across the community water system(s) serving Diamond Bar, going back to the earliest EPA record. None were health-based; the records are monitoring or reporting violations (a required test or report was late or missed). Each is listed by system below, with its status.

2

Community water systems
~232

People served (EPA-reported)
October 2026

EPA records reviewed through

Compare with another city →

What the EPA has on record, by system

Fire Suppression Camp #19

125 served · surface water · PWSID CA1900901

Monitoring Lead and Copper Rule: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded once in July 2018. All have since returned to compliance, per EPA records.

California Conservation Camp #14

107 served · surface water · PWSID CA1900007

Monitoring Lead and Copper Rule: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 2 times between July 2018 and January 2022. All have since returned to compliance, per EPA records.

What this means

A health-based violation means a contaminant was recorded above the limit the EPA tracks for it. A monitoring or reporting violation means a required test or report was late or missed — not that a contaminant was measured above a limit. “Returned to compliance” means the EPA recorded the issue as resolved.

This page summarizes the EPA's own records and does not assess whether your water is safe to drink. For the most current details, you can verify every record directly with the EPA, and contact your water system with questions.

Source: U.S. EPA Envirofacts SDWIS, retrieved October 2026. Records cover the EPA's full reporting history for these systems. Verify at EPA ECHO.