CITY OF MODESTO - GRAYSON

MODESTO, CA · ~914 people served

Check your exact address → MODESTO overview

100

Excellent

PurityRadar safety score

PWSID

CA5010033

State

California

City

MODESTO

Population served

914

Primary source

Groundwater

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 Jul 2019. Official EPA record →

Max contaminant level (MCL) · Nitrate health-based began Jun 2003 Resolved

Max contaminant level (MCL) · Nitrate health-based began Dec 1998 Resolved

Max contaminant level (MCL) · Nitrate health-based began Dec 1997 Resolved

Max contaminant level (MCL) · Nitrate health-based began Jul 1995 Resolved

Max contaminant level (MCL) · Nitrate health-based began Apr 1995 Resolved

Max contaminant level (MCL) · Total coliform health-based began Apr 1993 Resolved

Recent enforcement actions

State action · SOX Jul 2019
State action · SOX Jul 2019
State action · SOX Jul 2003
State action · SOX Jul 2003
State action · SFL Jul 2003
State action · SFL May 2001
State action · SFL Feb 1999
State action · SOX Feb 1999

Area water-quality monitoring

Environmental monitoring (rivers, wells, intakes) recorded in this system’s service area in the EPA/USGS Water Quality Portal since 2018 — source/ambient water, not finished tap water. Context for the watershed, not a reading from your tap.

ContaminantMedian · max · samples

Nitrate

1 station · latest Aug 2020

15.9 · max 15.9 mg/l as N · 2

Arsenic

1 station · latest Aug 2020

1.2 · max 1.2 ug/l · 1

Fluoride

1 station · latest Aug 2020

0.12 · max 0.12 mg/l · 1

Uranium

1 station · latest Aug 2020

3.31 · max 3.31 ug/l · 1

Source: Water Quality Portal (EPA/USGS/state agencies). Values are as-reported and aren’t health thresholds.

This profile is built from EPA public records for system CA5010033 — 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.