Public EPA test results
What EPA records show for Estero Municipal Improvement District
EPA system ID CA4110021 · serves San Mateo County, CA · about 36,556 people (EPA records)
Here's what EPA has on file for this water system: its testing for newer contaminants like PFAS (UCMR 5), lead testing and violations. It's not a test of your tap, and there's no Water Score here.
Public EPA test results
Estero Municipal Improvement District (EPA CA4110021)
What EPA records show for Estero Municipal Improvement District, as of October 14, 2026
We found no health-standard violations in EPA's records for this system (CA4110021) since July 1, 2021, as of October 14, 2026.
Source: EPA ECHO record for Estero Municipal Improvement District (SDWIS). Data as of October 14, 2026.
Lead: 9 in 10 homes tested came in at or below 0 ppb, at or below EPA's 15 ppb action level (latest EPA result for a testing period that ran on or after July 1, 2021: Jan 1, 2023–Dec 31, 2025). This is one number for the whole water system, from homes the utility tested. It isn't a result for your home.
EPA's UCMR 5 testing looked for 30 contaminants here and found none.
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 Estero Municipal Improvement District use chloramine?
We didn't find chloramine in Estero Municipal Improvement District's EPA treatment records. That's not a complete list; your utility's annual water quality report says which disinfectant it uses.
What EPA records show for this system
Reported results in EPA records (data as of Oct 14–15, 2026)