PURISSIMA HILLS WATER DISTRICT

LOS ALTOS HILLS, CA · ~6,245 people served

Check your exact address → LOS ALTOS HILLS overview

100

Excellent

PurityRadar safety score

PWSID

CA4310021

State

California

City

LOS ALTOS HILLS

Population served

6,245

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 Oct 2023. Official EPA record →

Monitoring & reporting · Lead & Copper Rule began Jan 2020 Resolved

Max contaminant level (MCL) · Total coliform health-based began Nov 1999 Resolved

Treatment technique · EPA contaminant 0200 health-based began Aug 1998 Resolved

Treatment technique · EPA contaminant 0200 health-based began Mar 1995 Resolved

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

Recent enforcement actions

State action · SOX Oct 2023
State action · SFL Dec 2022
State action · SOX Jul 2000
State action · SOX Apr 2000
State action · SIA Feb 2000
State action · SIF Feb 2000
State action · SIE Feb 2000
State action · SOX Dec 1999

This profile is built from EPA public records for system CA4310021 — 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.