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ZIP Code 91770 Water Quality
California · 225,761 people served · 15 water systems
B
GoodZIP code 91770 is in California and is a mid-sized community from a drinking-water-service perspective, with 225,761 people served by 15 EPA-registered public water systems. It corresponds to ROSEMEAD.
Within ZIP code 91770, the EPA Safe Drinking Water Information System (SDWIS) records 1 health-based violation during the past five years across 15 water systems serving this postal area. The grade of B reflects the aggregate compliance pattern, not the current daily water quality.
Last updated: 2026-05-18 · Source: EPA SDWIS
ZIP Code Location
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Cities in ZIP 91770
Water Systems Serving 91770
CAL-AM WATER COMPANY - EAST PASADENA
PWSID: CA1910020
9,949 served
GOLDEN SANDS MOBILE HOME PARK
PWSID: CA1900649
450 served
AMARILLO MUTUAL WATER COMPANY
PWSID: CA1910002
3,134 served
CAL AMERICAN WATER CO
PWSID: CA5610040
66,809 served
CAL AMERICAN WC - LAS POSAS ESTATES
PWSID: CA5610081
2,039 served
CAL AMERICAN WATER COMPANY - PIRU
PWSID: CA5610021
2,003 served
CAL AMERICAN - YERBA BUENA
PWSID: CA5610006
690 served
CAL AMERICAN WC - RIO PLAZA
PWSID: CA5610010
1,709 served
BELLFLOWER MUNICIPAL WATER SYSTEM
PWSID: CA1910018
5,999 served
CAL/AM WATER COMPANY - BALDWIN HILLS
PWSID: CA1910052
20,724 served
CAL/AM WATER COMPANY - SAN MARINO
PWSID: CA1910139
47,995 served
CAL-AM WATER COMPANY - DUARTE
PWSID: CA1910186
24,773 served
SAN GABRIEL COUNTY WD
PWSID: CA1910144
39,345 served
SCE/BIG CREEK POWERHOUSE 1
PWSID: CA1009111
104 served
SCE BISHOP CREEK PLANT 4
PWSID: CA1400078
38 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.
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