- EPA's UCMR 5 testing looked for 30 contaminants here and found 1.
- Lithium: found in 8 of 10 samples, average 38.1 µg/L, highest 57.4 µg/L (EPA UCMR 5 testing, Jun 2024–Mar 2025)
- Lead, 90th percentile: 0 ppb at the latest result in EPA records for a monitoring period that ran on or after July 1, 2021, at or below EPA's 15 ppb action level (EPA SDWIS, monitoring period Jan 1, 2022–Dec 31, 2024). The 90th percentile is a system-wide measure from homes sampled under EPA's lead rule; it isn't a result for your home.
Public EPA test results
San Juan Capistrano, CA tap water: what EPA records show
EPA CA3010030 · serves San Juan Capistrano, CA · about 35,309 people (EPA SDWIS)
This report shows EPA's federal records for this water system: UCMR 5 testing, lead testing and violations. It isn't a test of the water at your tap, and it has no Water Score.
Public EPA test results
Santa Margarita Water District-Id9 (EPA CA3010030)
EPA data as of October 14, 2026. For San Juan Capistrano's main utility, Santa Margarita Water District-Id9: We found no health-based violations in EPA's records for this system (CA3010030) since July 1, 2021, as of October 14, 2026. PFOA and PFOS were not detected at or above EPA's reporting level in EPA's UCMR 5 testing.
What EPA records show for Santa Margarita Water District-Id9, as of October 14, 2026
We found no health-based violations in EPA's records for this system (CA3010030) since July 1, 2021, as of October 14, 2026.
Source: EPA ECHO record for Santa Margarita Water District-Id9 (SDWIS). Data as of October 14, 2026.
Lead, 90th percentile: 0 ppb at the latest result in EPA records for a monitoring period that ran on or after July 1, 2021, at or below EPA's 15 ppb action level (EPA SDWIS, monitoring period Jan 1, 2022–Dec 31, 2024). The 90th percentile is a system-wide measure from homes sampled under EPA's lead rule; it isn't a result for your home.
EPA's UCMR 5 testing looked for 30 contaminants here and found 1.
PFOA and PFOS were not detected at or above EPA's reporting level in EPA's UCMR 5 testing.
Source: EPA records (SDWIS, UCMR 5). SDWIS: data as of Oct 14, 2026. EPA UCMR 5 data, samples through June 2026.
Your water bill names your utility.
Does Santa Margarita Water District-Id9 use chloramine?
EPA treatment records (state-reported) list chloramines for Santa Margarita Water District-Id9. EPA record