CWSC LOS ALTOS SUBURBAN

SAN JOSE, CA · ~69,973 people served

Check your exact address → SAN JOSE overview

100

Excellent

PurityRadar safety score

PWSID

CA4310001

State

California

City

SAN JOSE

Population served

69,973

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

Latest detections from EPA’s UCMR5 monitoring (through Apr 2024). Levels in parts per trillion (ppt).

PFHxS

Perfluorohexanesulfonic acid

3.1 ppt

limit 10 ppt

Below EPA limit

Violations & enforcement

Violations on record

Unaddressed

Health-based

Enforcement actions

From EPA ECHO (SDWIS), most recent enforcement Jan 2019. Official EPA record →

Monitoring & reporting · EPA contaminant 2037 began Jan 2002 Resolved

Monitoring & reporting · Nitrate began Mar 1995 Resolved

Max contaminant level (MCL) · Total coliform health-based began Nov 1992 Resolved

Recent enforcement actions

State action · SOX Jan 2019
State action · SOX Dec 2005
State action · SOX Apr 2000
State action · SOX May 1996
State action · SIA May 1996
EPA/federal action · EOX Dec 1993
EPA/federal action · EOX Dec 1992

This profile is built from EPA public records for system CA4310001 — 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.