How does Cupertino tap water hold up under EPA scrutiny? Above average for CA — documented violations are uncommon and the safety grade reflects a clean overall record.

Data: EPA SDWIS Last verified: 2026-06-03

Overview

We track water quality and home safety data for 2 ZIP codes in Cupertino, California (population ~61,109), covering 5 community water systems serving approximately 1,411,799 people region-wide.

No EPA violations recorded across any ZIP codes in Cupertino — an excellent indicator of water quality.

Home Safety Score

Average Home Safety Score for Cupertino: B (71/100)

The score combines three factors:

Factor	What It Measures
Water Quality	EPA violations and compliance history
Lead Levels	90th percentile lead concentration vs EPA action level
Radon Risk	EPA radon zone classification

Water Sources

Cupertino water systems draw from: Surface water.

Lead & Copper

• Lead data: not yet available for Cupertino
• 0 ZIP codes exceed the EPA lead action level

Radon Risk

Dominant radon zone: Zone 2 (Moderate Risk)

• Zone 1 (High): 0 ZIP codes
• Zone 2 (Moderate): 2 ZIP codes
• Zone 3 (Low): 0 ZIP codes

The EPA recommends testing homes in Zone 1 and Zone 2 areas for radon.

Areas with No Violations

All ZIP Codes in Cupertino

• 95014 [B]
• 95015 [B]

Data Sources

• Water quality: EPA Safe Drinking Water Information System (SDWIS)
• Lead/copper: EPA Lead and Copper Rule sampling data
• Radon: EPA Map of Radon Zones

Updated daily.

How Remediation Costs Compare in Cupertino

Given current Cupertino valuations, the remediation-to-property-value ratio is low — most homeowners are looking at a proportionally modest share that fits within routine financial planning.

Median Home Value

$2.0M

Est. Remediation

$1,600

Remediation as % of home value 0.1%

Remediation costs in Cupertino are relatively low compared to home values. The $800–$2,450 estimated range is a small fraction of median property value. Home values are 171% above the California average.

Cupertino: Flood History & Water Damage Risk

Over the multi-decade window covered by the National Flood Insurance Program, Cupertino has accumulated 24 claims — a total that suggests more than isolated flood exposure. With 50% of ZIP codes in designated flood zones, the water-quality implications of flooding move from hypothetical to periodically relevant: treatment intake can be compromised, wells can be infiltrated, and distribution backflow can occur.

24

Total FEMA Flood Claims

$37,024

Avg Claim Payout

50%

ZIPs in FEMA Flood Zones

~1

Est. Claims/Year

Cupertino has a moderate flood history with 24 FEMA claims averaging $37,024 per payout. 50% of ZIP codes fall within FEMA flood zones. Flood events can contaminate drinking water and overwhelm treatment systems.

How flooding affects water quality: Flood events can introduce sewage, agricultural runoff, and industrial chemicals into water supplies. Even after floodwaters recede, contamination can persist in wells and aging infrastructure. Flood damage can add significantly to the estimated <strong>$1,600</strong> remediation cost per household.

Residents in flood-prone areas should consider flood insurance even outside FEMA zones — over 25% of flood claims come from low-to-moderate risk areas. After any flood event, test your water before drinking.

Source: FEMA National Flood Insurance Program (NFIP) claims data, FEMA flood zone designations.