- EPA's UCMR 5 testing looked for 30 contaminants here and found 3.
- PFOS (a PFAS): found in 2 of 6 samples, average 5 ppt, highest 17 ppt (EPA UCMR 5 testing, Jan 2024–Oct 2024) PFOA or PFOS averaged above 4.0 ppt in UCMR 5 testing
- PFBS (a PFAS): found in 2 of 6 samples, average 1.4 ppt, highest 5 ppt (EPA UCMR 5 testing, Jan 2024–Oct 2024)
- PFHxS (a PFAS): found in 1 of 6 samples, average 0.60 ppt, highest 3.5 ppt (EPA UCMR 5 testing, Jan 2024–Oct 2024)
- 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
Can you drink Lathrop tap water? What EPA records show
EPA CA3910015 · serves Lathrop, CA · about 38,596 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
City of Lathrop (EPA CA3910015)
EPA data as of October 14, 2026. For Lathrop's main utility, City of Lathrop: We found no health-based violations in EPA's records for this system (CA3910015) since July 1, 2021, as of October 14, 2026. This water system averaged above 4.0 ppt for PFOA or PFOS in EPA's UCMR 5 testing.
What EPA records show for City of Lathrop, as of October 14, 2026
We found no health-based violations in EPA's records for this system (CA3910015) since July 1, 2021, as of October 14, 2026.
Source: EPA ECHO record for City of Lathrop (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.
This water system averaged above 4.0 ppt for PFOA or PFOS in EPA's UCMR 5 testing.
EPA's UCMR 5 testing looked for 30 contaminants here and found 3.
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 City of Lathrop use chloramine?
We didn't find chloramine in City of Lathrop's EPA treatment records. That's not a complete list; your utility's annual water quality report says which disinfectant it uses.