- EPA's UCMR 5 testing looked for 30 contaminants here and found 8.
- Lithium: found in 13 of 86 samples, average 2.01 µg/L, highest 21 µg/L (EPA UCMR 5 testing, Nov 2023–Aug 2024)
- PFOS (a PFAS): found in 15 of 86 samples, average 1.4 ppt, highest 26 ppt (EPA UCMR 5 testing, Nov 2023–Sep 2024)
- PFHxS (a PFAS): found in 13 of 86 samples, average 0.70 ppt, highest 9.3 ppt (EPA UCMR 5 testing, Nov 2023–Sep 2024)
- PFOA (a PFAS): found in 8 of 86 samples, average 0.50 ppt, highest 8.6 ppt (EPA UCMR 5 testing, Nov 2023–Sep 2024)
- PFPeA (a PFAS): found in 8 of 86 samples, average 0.40 ppt, highest 6.7 ppt (EPA UCMR 5 testing, Nov 2023–Sep 2024)
- PFHxA (a PFAS): found in 8 of 86 samples, average 0.40 ppt, highest 6.1 ppt (EPA UCMR 5 testing, Nov 2023–Sep 2024)
- PFBS (a PFAS): found in 2 of 86 samples, average 0.10 ppt, highest 4.3 ppt (EPA UCMR 5 testing, Nov 2023–Sep 2024)
- PFHpA (a PFAS): found in 1 of 86 samples, average 0.0 ppt, highest 3.6 ppt (EPA UCMR 5 testing, Nov 2023–Sep 2024)
- Lead, 90th percentile: 12 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, 2025–Dec 31, 2027). 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 Modesto tap water? What EPA records show
EPA CA5010010 · serves Modesto, CA · about 218,915 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
Modesto, City of (EPA CA5010010)
ScoreYourWater.com gives no verdict on your tap water; it shows what the public records say, as of October 14, 2026. For Modesto's main utility, Modesto, City of: We found no health-based violations in EPA's records for this system (CA5010010) since July 1, 2021, as of October 14, 2026. EPA's UCMR 5 testing looked for 30 contaminants here and found 8.
What EPA records show for Modesto, City of, as of October 14, 2026
We found no health-based violations in EPA's records for this system (CA5010010) since July 1, 2021, as of October 14, 2026.
Source: EPA ECHO record for Modesto, City of (SDWIS). Data as of October 14, 2026.
Lead, 90th percentile: 12 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, 2025–Dec 31, 2027). 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 8.
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 Modesto, City of use chloramine?
We didn't find chloramine in Modesto, City of's EPA treatment records. That's not a complete list; your utility's annual water quality report says which disinfectant it uses.