Apr 15, 2026 · 7 min read
PFAS "Forever Chemicals" in US Drinking Water: 2026 Update
PFAS contamination affects an estimated 200 million Americans. Here's what the latest EPA enforcement means for your tap water.
ZIP Code 91791 Water Quality
California · 11,415 people served · 11 water systems
F
FailingZIP code 91791 is in California and is a small city from a drinking-water-service perspective, with 11,415 people served by 11 EPA-registered public water systems. It corresponds to WEST COVINA.
Within ZIP code 91791, the EPA Safe Drinking Water Information System (SDWIS) records 20 health-based violations during the past five years across 11 water systems serving this postal area. The grade of F reflects the aggregate compliance pattern, not the current daily water quality.
Last updated: 2026-05-18 · Source: EPA SDWIS
ZIP Code Location
Loading map...
Cities in ZIP 91791
Water Systems Serving 91791
COVINA IRRIGATING CO.
PWSID: CA1910128
0 served
VALENCIA HEIGHTS WATER CO.
PWSID: CA1910163
7,775 served
MECKS WHISPERING PINES II LLC
PWSID: IN5243033
598 served
ARBOR VILLAGE
PWSID: MI0040223
670 served
GUN RIVER ESTATES WEST
PWSID: MI0040029
152 served
GUN RIVER MOBILE ESTATES
PWSID: MI0040011
415 served
ARROWHEAD LAKE MHP
PWSID: OH4800112
327 served
SHERWOOD FOREST MHP PWS
PWSID: OH1901112
578 served
SWANTON MEADOWS
PWSID: OH2601212
180 served
BRADY HILLS ML
PWSID: PA5100869
400 served
RECREACRES MHC LLC
PWSID: WI7500138
320 served
About ZIP-code water data
Postal-code level water quality data is built up from the underlying water systems — multiple ZIPs may share a single utility, and a single ZIP can span multiple utilities. For property-level information, contact the specific utility serving your address. EPA data on this page was last refreshed on 2026-05-18.
From the Blog
Photo by Bluewater Sweden on Unsplash
Mar 22, 2026 · 6 min read
How to Read Your Annual Water Quality Report (CCR)
Your water utility is legally required to send you a Consumer Confidence Report every year. Here's how to actually understand it.
Photo by Louis Hansel on Unsplash
Mar 5, 2026 · 9 min read
Lead in Tap Water: The Complete 2026 Guide
Lead enters drinking water through old pipes and fixtures. Here's how to identify your risk and what to do about it.
Photo by Eduardo Casajús Gorostiaga on Unsplash
Feb 18, 2026 · 5 min read
What Is an EPA Maximum Contaminant Level (MCL)?
MCLs are the foundation of US drinking water safety. Here's how they're set and what they mean for your tap.
Photo by Naja Bertolt Jensen on Unsplash
