CA / Costa Mesa
CA · Tap water records
Costa Mesa tap water, in plain English
Here is what the EPA's own data shows about tap water in Costa Mesa. According to EPA SDWIS data retrieved June 2026, Costa Mesa is served by 6 active community water systems, together reported to serve about 110,866 people.
As of June 2026, EPA records show 92 violations across the community water system(s) serving Costa Mesa, going back to the earliest EPA record. 55 of these are classified by the EPA as health-based (a contaminant recorded above the limit the EPA tracks); the rest are monitoring or reporting violations. Each is listed by system below, with its status.
What the EPA has on record, by system
Mesa Water District
110,000 served · surface water · PWSID CA3010004 - Monitoring Gross Alpha Particle Activity: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded once in January 2010. All have since returned to compliance, per EPA records.
- Monitoring Combined Uranium: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded once in January 2010. All have since returned to compliance, per EPA records.
Lake Wohlford Resort
250 served · surface water · PWSID CA3700919 - Health-based Surface Water Treatment Rule: a health-based violation (a contaminant recorded above the limit the EPA tracks), recorded once in July 2018. The EPA record for these does not include a measured level. EPA records do not show all of these as returned to compliance.
- Monitoring Surface Water Treatment Rule: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded once in January 2017. All have since returned to compliance, per EPA records.
- 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 January 2014. All have since returned to compliance, per EPA records.
Pine Valley Trailer Park
200 served · groundwater · PWSID CA3701961 - Health-based Iron: a health-based violation (a contaminant recorded above the limit the EPA tracks), recorded 24 times between July 2020 and October 2024. The EPA record lists a level of 1.01 MG/L; the limit (MCL) is 0.3 MG/L. EPA records do not show all of these as returned to compliance.
- Health-based Manganese: a health-based violation (a contaminant recorded above the limit the EPA tracks), recorded 30 times between April 2020 and October 2024. The EPA record lists a level of 0.163 MG/L; the limit (MCL) is 0.005 MG/L. EPA records do not show all of these as returned to compliance.
- Monitoring Iron: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 16 times between July 2021 and July 2024. EPA records do not show all of these as returned to compliance.
- Monitoring Manganese: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 16 times between July 2021 and July 2024. EPA records do not show all of these as returned to compliance.
Rolling Hills Community, Llc
200 served · groundwater · PWSID NY3300992 As of June 2026, EPA records show no reported violations for this system in the period covered. This is not a guarantee about every substance, or about the water inside your home's plumbing.
Brookside Mobile Home Park
126 served · groundwater · PWSID CA1400059 - 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 1993. All have since returned to compliance, per EPA records.
Rustic Acres Mhp
90 served · groundwater · PWSID WI4430494 As of June 2026, EPA records show no reported violations for this system in the period covered. This is not a guarantee about every substance, or about the water inside your home's plumbing.
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 June 2026. Records cover the EPA's full reporting history for these systems. Verify at EPA ECHO.