ESTERO MUNICIPAL IMPROVEMENT DISTRICT

FOSTER CITY, CA · ~36,556 people served

Check your exact address → FOSTER CITY overview

100

Excellent

PurityRadar safety score

PWSID

CA4110021

State

California

City

FOSTER CITY

Population served

36,556

Primary source

SWP

Score history

No change since tracking began Jun 18, 2026.

Jun 18, 2026 · score 100 Jun 18, 2026 · score 100

2 score updates logged since tracking began Jun 18, 2026. Each future EPA re-score adds a point.

PFAS & contaminant readings

No PFAS detections are on record for this system from EPA’s UCMR5 monitoring (2023–25). Absence of a detection isn’t a guarantee — not every system was sampled, and this dataset doesn’t cover other contaminants.

Violations & enforcement

Violations on record

Unaddressed

Health-based

Enforcement actions

From EPA ECHO (SDWIS), most recent enforcement Feb 2023. Official EPA record →

Monitoring & reporting · Total trihalomethanes (TTHM) began Jul 2022 Resolved

Max contaminant level (MCL) · Total coliform health-based began Oct 2007 Resolved

Monitoring & reporting · Lead & Copper Rule began Jun 1993 Resolved

Treatment technique · EPA contaminant 0200 health-based began Apr 1992 Resolved

Recent enforcement actions

State action · SIA Feb 2023
State action · SOX Feb 2023
State action · SOX Nov 2007
State action · SFL Nov 2007
State action · SOX Apr 2000
State action · SOX Apr 1992

This profile is built from EPA public records for system CA4110021 — SDWIS violations and UCMR5 PFAS sampling. The score is system-level and can’t account for your home’s plumbing (older pipes can add lead at the tap). For health decisions, check your exact address, read the utility’s Consumer Confidence Report, and confirm with your provider.