Here is what the EPA's own data shows about tap water in Irvine. According to EPA SDWIS data retrieved July 2026, Irvine is served by 15 active community water systems, together reported to serve about 448,371 people.
As of July 2026, EPA records show 113 violations across the community water system(s) serving Irvine, going back to the earliest EPA record. 38 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.
Monitoring Revised Total Coliform Rule: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 4 times in September 2020. All have since returned to compliance, per EPA records.
Big Basin Water Company
1,120 served · groundwater · PWSID CA4410001
Monitoring Revised Total Coliform Rule: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 3 times between October 2021 and June 2022. All have since returned to compliance, per EPA records.
Monitoring TTHM: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 12 times between July 2020 and January 2022. EPA records do not show all of these as returned to compliance.
Monitoring Total Haloacetic Acids (HAA5): a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 12 times between July 2020 and January 2022. EPA records do not show all of these as returned to compliance.
Monitoring Nitrate: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 2 times in January 2018. EPA records do not show all of these as returned to compliance.
Monitoring Arsenic: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 2 times in January 2018. EPA records do not show all of these as returned to compliance.
Monitoring Nitrite: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 2 times in January 2018. EPA records do not show all of these as returned to compliance.
Monitoring Simazine: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 2 times in January 2018. EPA records do not show all of these as returned to compliance.
Cabana Holiday Ws
506 served · groundwater · PWSID CA2700522
Monitoring Consumer Confidence Rule: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded once in July 2011. All have since returned to compliance, per EPA records.
Arbor Mobile Home Park Ws
340 served · groundwater · PWSID CA3900831
Monitoring Consumer Confidence Rule: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded once in July 2002. 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 April 2000. All have since returned to compliance, per EPA records.
Saint Marie Mobile Home Park
320 served · groundwater · PWSID CA4200842
Health-based LEAD AND COPPER RULE REVISIONS: a health-based violation (a contaminant recorded above the limit the EPA tracks), recorded once in October 2024. The EPA record for these does not include a measured level. EPA records do not show all of these as returned to compliance.
Health-based Nitrate: a health-based violation (a contaminant recorded above the limit the EPA tracks), recorded 3 times between January 2019 and January 2020. The EPA record lists a level of 10.5 MG/L; the limit (MCL) is 10 MG/L. EPA records do not show all of these as returned to compliance.
Monitoring LEAD AND COPPER RULE REVISIONS: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded once in October 2024. EPA records do not show all of these as returned to compliance.
Monitoring Consumer Confidence Rule: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 2 times between July 2002 and July 2006. All have since returned to compliance, per EPA records.
Riverdale Estates
300 served · groundwater · PWSID CA3301040
Monitoring Consumer Confidence Rule: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 4 times between July 2004 and July 2019. All have since returned to compliance, per EPA records.
Monitoring Antimony, Total: 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.
Monitoring Calcium: 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.
Monitoring Sulfate: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded once in January 2014. EPA records do not show all of these as returned to compliance.
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 Radium-228: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded once in January 2009. All have since returned to compliance, per EPA records.
Monitoring Coliform (TCR): a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded once in August 1999. 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 July 1993. All have since returned to compliance, per EPA records.
Dot Mhp
229 served · groundwater · PWSID CO0119501
As of July 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.
Table Rock Mobile Estates (South)
150 served · groundwater · PWSID OR4101052
As of July 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.
Thirty-Twenty Estates
125 served · groundwater · PWSID MN1620019
As of July 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.
Monett Village
112 served · groundwater · PWSID MO5048177
As of July 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.
Resthaven Mobile Home Park
99 served · groundwater · PWSID CA4000654
Health-based Selenium: a health-based violation (a contaminant recorded above the limit the EPA tracks), recorded 33 times between October 2020 and October 2025. The EPA record for these does not include a measured level. EPA records do not show all of these as returned to compliance.
Alturas Fillmore Mhp
99 served · groundwater · PWSID CA5601106
Monitoring Revised Total Coliform Rule: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 2 times in July 2022. All have since returned to compliance, per EPA records.
Monitoring E. COLI: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded once in June 2014. All have since returned to compliance, per EPA records.
Boardwalk Mhc
71 served · groundwater · PWSID WI4690405
As of July 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.
Twin Creeks Mobile And Rv Village
50 served · groundwater · PWSID CA1700580
Health-based LEAD AND COPPER RULE REVISIONS: a health-based violation (a contaminant recorded above the limit the EPA tracks), recorded once in October 2024. The EPA record for these does not include a measured level. EPA records do not show all of these as returned to compliance.
Monitoring LEAD AND COPPER RULE REVISIONS: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded once in October 2024. EPA records do not show all of these as returned to compliance.
Monitoring Lead and Copper Rule: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 12 times between July 1993 and January 2021. All have since returned to compliance, per EPA records.
Monitoring contaminant code null: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 2 times between January 2016 and January 2017. All have since returned to compliance, per EPA records.
Monitoring Nitrate: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded once in January 2015. All have since returned to compliance, per EPA records.
Table Rock Mobile Estates (North)
50 served · groundwater · PWSID OR4101540
As of July 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 July 2026. Records cover the EPA's full reporting history for these systems. Verify at EPA ECHO.