Tap water quality for ZIP 91789

4 community water systems linked to this ZIP, largest first.

What this means for you in ZIP 91789

Is it safe to drink right now?
Based on the latest EPA data, Walnut Valley Water District has no unresolved health-based violations from the past year. Water that meets federal standards is generally considered safe to drink for most healthy people.
Should I use a filter?
Optional. Nothing in this data strongly calls for one. Many people still filter for chlorine taste and odor.
What kind of filter?
For taste and odor (chlorine/chloramine), an NSF/ANSI 42 pitcher or faucet filter is enough. See matched standards and product picks.

This is general information from public EPA data, not medical advice. Lead often comes from a home’s own pipes, so only a test of your tap can tell your exposure. If you are pregnant, caring for an infant, or have a weakened immune system, ask your doctor or health department.

Shown for the largest system linked to this ZIP. Check your water bill to confirm your provider.

Filters matched to Walnut Valley Water District

FILTER PICKS

Look for filters certified (NSF, IAPMO or WQA) to these standards for the specific contaminant. Buttons open the maker’s page or an Amazon search; use “Check NSF listing” to verify a model’s claims. No affiliate links yet — grades are never sold.

Chlorine/chloramine taste

NSF/ANSI 42
Aquasana Clean Water Pitcher ~$35
Pitcher for chlorine taste/odor; check the NSF/ANSI 42 listing for the exact model.
Search on Amazon →
Check NSF listing · Not an affiliate link · disclosure
Brita Elite Filter ~$20–40
Common faucet/pitcher option; confirm the 42 claim on the box.
View on Brita →
Check NSF listing · Not an affiliate link · disclosure

Annual water quality report

Utilities must publish a Consumer Confidence Report every year by July 1. Find it on the utility’s website or ask them directly; EPA explains how. · Full report →

Water systems for this ZIP

A

Walnut Valley Water District

Serves 100,941 people · Surface water · Full report →
No health-based violations in the last 5 years; PFAS tested (UCMR 5), none above federal limits; Lead 90th percentile below the action level (2024).
A

Suburban Water Systems-San Jose

Serves 170,523 people · Surface water · Full report →
No health-based violations in the last 5 years; 1 monitoring/reporting violation; PFAS tested (UCMR 5), none above federal limits; Lead 90th percentile below the action level (2025).
B

Gswc-San Dimas

Serves 56,564 people · Surface water · Full report →
No health-based violations in the last 5 years; PFOA/PFOS average above the 4 ppt federal limit: PFOS; Lead 90th percentile below the action level (2026).
A

Three Valleys MWD

Population not reported (often a wholesaler) · Surface water · Full report →
No health-based violations in the last 5 years; No UCMR 5 PFAS results on file.
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