CO / Larkspur
CO · Tap water records
Larkspur tap water, in plain English
Here is what the EPA's own data shows about tap water in Larkspur. According to EPA SDWIS data retrieved June 2026, Larkspur is served by 2 active community water systems, together reported to serve about 4,165 people.
As of June 2026, EPA records show 175 violations across the community water system(s) serving Larkspur, going back to the earliest EPA record. 20 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
Perry Park Wsd
3,890 served · surface water · PWSID CO0118045 - Monitoring E. COLI: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 4 times in November 2023. EPA records do not show all of these as returned to compliance.
- Monitoring Long Term 2 Enhanced Surface Water Treatment Rule: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 3 times in February 2023. All have since returned to compliance, per EPA records.
- Monitoring Surface Water Treatment Rule: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 7 times between April 2021 and December 2022. EPA records do not show all of these as returned to compliance.
- Monitoring TTHM: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 7 times between January 2019 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 7 times between January 2019 and January 2022. EPA records do not show all of these as returned to compliance.
- Monitoring Combined Radium (-226 and -228): a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 5 times between April 2020 and January 2022. EPA records do not show all of these as returned to compliance.
- Monitoring Interim Enhanced Surface Water Treatment Rule: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 4 times between April 2021 and June 2021. 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 2 times in January 2019. All have since returned to compliance, per EPA records.
- Monitoring Endrin: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 2 times in January 2017. All have since returned to compliance, per EPA records.
- Monitoring BHC-GAMMA: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 2 times in January 2017. All have since returned to compliance, per EPA records.
- Monitoring Methoxychlor: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 2 times in January 2017. All have since returned to compliance, per EPA records.
- Monitoring Toxaphene: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 2 times in January 2017. All have since returned to compliance, per EPA records.
- Monitoring Dalapon: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 2 times in January 2017. All have since returned to compliance, per EPA records.
- Monitoring Diquat: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 2 times in January 2017. All have since returned to compliance, per EPA records.
- Monitoring Endothall: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 2 times in January 2017. All have since returned to compliance, per EPA records.
- Monitoring Di(2-ethylhexyl) adipate: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 2 times in January 2017. All have since returned to compliance, per EPA records.
- Monitoring OXAMYL: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 2 times in January 2017. All have since returned to compliance, per EPA records.
- 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 2017. All have since returned to compliance, per EPA records.
- Monitoring Di(2-ethylhexyl) phthalate: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 2 times in January 2017. All have since returned to compliance, per EPA records.
- Monitoring Picloram: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 2 times in January 2017. All have since returned to compliance, per EPA records.
- Monitoring Dinoseb: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 2 times in January 2017. All have since returned to compliance, per EPA records.
- Monitoring Hexachlorocyclopentadiene: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 2 times in January 2017. All have since returned to compliance, per EPA records.
- Monitoring Aldicarb sulfoxide: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 2 times in January 2017. All have since returned to compliance, per EPA records.
- Monitoring Aldicarb sulfone: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 2 times in January 2017. All have since returned to compliance, per EPA records.
- Monitoring Carbofuran: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 2 times in January 2017. All have since returned to compliance, per EPA records.
- Monitoring Aldicarb: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 2 times in January 2017. All have since returned to compliance, per EPA records.
- Monitoring Atrazine: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 2 times in January 2017. All have since returned to compliance, per EPA records.
- Monitoring LASSO: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 2 times in January 2017. All have since returned to compliance, per EPA records.
- Monitoring Heptachlor: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 2 times in January 2017. All have since returned to compliance, per EPA records.
- Monitoring Heptachlor epoxide: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 2 times in January 2017. All have since returned to compliance, per EPA records.
- Monitoring 2,4-D: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 2 times in January 2017. All have since returned to compliance, per EPA records.
- Monitoring 2,4,5-TP: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 2 times in January 2017. All have since returned to compliance, per EPA records.
- Monitoring HEXACHLOROBENZENE: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 2 times in January 2017. All have since returned to compliance, per EPA records.
- Monitoring Benzo(a)pyrene: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 2 times in January 2017. All have since returned to compliance, per EPA records.
- Monitoring Pentachlorophenol: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 2 times in January 2017. All have since returned to compliance, per EPA records.
- Monitoring Total Polychlorinated Biphenyls (PCB): a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 2 times in January 2017. All have since returned to compliance, per EPA records.
- Monitoring 1,2-DIBROMO-3-CHLOROPROPANE: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 2 times in January 2017. All have since returned to compliance, per EPA records.
- Monitoring ETHYLENE DIBROMIDE: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 2 times in January 2017. All have since returned to compliance, per EPA records.
- Monitoring Chlordane: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 2 times in January 2017. All have since returned to compliance, per EPA records.
Larkspur Town Of
275 served · groundwater · PWSID CO0118030 - Health-based Combined Radium (-226 and -228): a health-based violation (a contaminant recorded above the limit the EPA tracks), recorded 20 times between April 2018 and October 2023. The EPA record lists a level of 6.8 PCI/L; the limit (MCL) is 5 PCI/L. EPA records do not show all of these as returned to compliance.
- Monitoring Public Notice: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 9 times between May 2017 and February 2024. All have since returned to compliance, per EPA records.
- Monitoring 1,2,4-Trichlorobenzene: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 2 times in January 2023. All have since returned to compliance, per EPA records.
- Monitoring cis-1,2-Dichloroethylene: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 2 times in January 2023. All have since returned to compliance, per EPA records.
- Monitoring Xylenes, Total: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 2 times in January 2023. All have since returned to compliance, per EPA records.
- Monitoring DICHLOROMETHANE: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 2 times in January 2023. All have since returned to compliance, per EPA records.
- Monitoring o-Dichlorobenzene: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 2 times in January 2023. All have since returned to compliance, per EPA records.
- Monitoring p-Dichlorobenzene: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 2 times in January 2023. All have since returned to compliance, per EPA records.
- Monitoring Vinyl chloride: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 2 times in January 2023. All have since returned to compliance, per EPA records.
- Monitoring 1,1-Dichloroethylene: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 2 times in January 2023. All have since returned to compliance, per EPA records.
- Monitoring trans-1,2-Dichloroethylene: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 2 times in January 2023. All have since returned to compliance, per EPA records.
- Monitoring 1,2-Dichloroethane: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 2 times in January 2023. All have since returned to compliance, per EPA records.
- Monitoring 1,1,1-Trichloroethane: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 2 times in January 2023. All have since returned to compliance, per EPA records.
- Monitoring Carbon tetrachloride: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 2 times in January 2023. All have since returned to compliance, per EPA records.
- Monitoring 1,2-Dichloropropane: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 2 times in January 2023. All have since returned to compliance, per EPA records.
- Monitoring Trichloroethylene: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 2 times in January 2023. All have since returned to compliance, per EPA records.
- Monitoring 1,1,2-Trichloroethane: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 2 times in January 2023. All have since returned to compliance, per EPA records.
- Monitoring Tetrachloroethylene: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 2 times in January 2023. All have since returned to compliance, per EPA records.
- Monitoring CHLOROBENZENE: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 2 times in January 2023. All have since returned to compliance, per EPA records.
- Monitoring Benzene: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 2 times in January 2023. All have since returned to compliance, per EPA records.
- Monitoring Toluene: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 2 times in January 2023. All have since returned to compliance, per EPA records.
- Monitoring Ethylbenzene: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 2 times in January 2023. All have since returned to compliance, per EPA records.
- Monitoring Styrene: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 2 times in January 2023. All have since returned to compliance, per EPA records.
- Monitoring Combined Radium (-226 and -228): a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded once in January 2022. 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 2019. All have since returned to compliance, per EPA records.
- 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 2018. 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 June 2026. Records cover the EPA's full reporting history for these systems. Verify at EPA ECHO.