Gswc - Southwest

Published drinking-water records and contacts for Gswc - Southwest. System CA1910155. Review sources and dates; not a real-time water assessment.

System ID: CA1910155
State or territory: CA
Published population served: 277740
System type (source code): CWS

Published records and dates

PFAS / lithium (EPA UCMR 5): 540 — 2024-06-18 – 2025-03-10
Lead and copper monitoring summaries: 39 — 1992-01-01 – 2026-12-31
California DDW laboratory results: 3156 — 2026-01-05 – 2026-07-13

Missing records here do not mean the provider did not test. Published records are not a real-time assessment of your tap water.

Read the provider’s annual water quality report

Report link listed: 2026-10-05. This is not the report’s sampling date.

Published testing results

Selected recent records are shown below. Different sampling locations and dates are not interchangeable. These excerpts are not a complete testing history.

“<” means below the stated reporting limit, not zero. A reported measurement alone is not a safety verdict. Read an example

EPA UCMR 5 — most recent imported sample per substance
Substance	Published result	Reporting limit	Sample date	Sampling location
11Cl-PF3OUdS	< 0.005 µg/L	0.005 µg/L	2025-03-10	West Basin 2A / WB2A
4:2 FTS	< 0.003 µg/L	0.003 µg/L	2025-03-10	West Basin 2A / WB2A
6:2 FTS	< 0.005 µg/L	0.005 µg/L	2025-03-10	West Basin 2A / WB2A
8:2 FTS	< 0.005 µg/L	0.005 µg/L	2025-03-10	West Basin 2A / WB2A
9Cl-PF3ONS	< 0.002 µg/L	0.002 µg/L	2025-03-10	West Basin 2A / WB2A
ADONA	< 0.003 µg/L	0.003 µg/L	2025-03-10	West Basin 2A / WB2A
HFPO-DA	< 0.005 µg/L	0.005 µg/L	2025-03-10	West Basin 2A / WB2A
NEtFOSAA	< 0.005 µg/L	0.005 µg/L	2025-03-10	West Basin 2A / WB2A
NFDHA	< 0.02 µg/L	0.02 µg/L	2025-03-10	West Basin 2A / WB2A
NMeFOSAA	< 0.006 µg/L	0.006 µg/L	2025-03-10	West Basin 2A / WB2A
PFBA	< 0.005 µg/L	0.005 µg/L	2025-03-10	West Basin 2A / WB2A
PFBS	< 0.003 µg/L	0.003 µg/L	2025-03-10	West Basin 2A / WB2A
PFDA	< 0.003 µg/L	0.003 µg/L	2025-03-10	West Basin 2A / WB2A
PFDoA	< 0.003 µg/L	0.003 µg/L	2025-03-10	West Basin 2A / WB2A
PFEESA	< 0.003 µg/L	0.003 µg/L	2025-03-10	West Basin 2A / WB2A
PFHpA	< 0.003 µg/L	0.003 µg/L	2025-03-10	West Basin 2A / WB2A
PFHpS	< 0.003 µg/L	0.003 µg/L	2025-03-10	West Basin 2A / WB2A
PFHxA	< 0.003 µg/L	0.003 µg/L	2025-03-10	West Basin 2A / WB2A
PFHxS	< 0.003 µg/L	0.003 µg/L	2025-03-10	West Basin 2A / WB2A
PFMBA	< 0.003 µg/L	0.003 µg/L	2025-03-10	West Basin 2A / WB2A
PFMPA	< 0.004 µg/L	0.004 µg/L	2025-03-10	West Basin 2A / WB2A
PFNA	< 0.004 µg/L	0.004 µg/L	2025-03-10	West Basin 2A / WB2A
PFOA	< 0.004 µg/L	0.004 µg/L	2025-03-10	West Basin 2A / WB2A
PFOS	< 0.004 µg/L	0.004 µg/L	2025-03-10	West Basin 2A / WB2A
PFPeA	< 0.003 µg/L	0.003 µg/L	2025-03-10	West Basin 2A / WB2A
PFPeS	< 0.004 µg/L	0.004 µg/L	2025-03-10	West Basin 2A / WB2A
PFTA	< 0.008 µg/L	0.008 µg/L	2025-03-10	West Basin 2A / WB2A
PFTrDA	< 0.007 µg/L	0.007 µg/L	2025-03-10	West Basin 2A / WB2A
PFUnA	< 0.002 µg/L	0.002 µg/L	2025-03-10	West Basin 2A / WB2A
lithium	44.6 µg/L	9 µg/L	2025-03-10	West Basin 2A / WB2A

Download all EPA UCMR 5 records (CSV)

Lead and copper: 90th-percentile summaries

These describe a monitoring period across sampled locations, not the result at your home. How to read the 90th percentile

Eight most recent imported monitoring summaries
Substance	Published 90th percentile	Monitoring period	Source quarter
Lead (PB90)	0.0017 mg/L	2024-01-01 – 2026-12-31	2026Q3
Lead (PB90)	0 mg/L	2020-01-01 – 2022-12-31	2026Q3
Lead (PB90)	0 mg/L	2020-01-01 – 2022-12-31	2026Q3
Lead (PB90)	0 mg/L	2017-01-01 – 2019-12-31	2026Q3
Lead (PB90)	0 mg/L	2017-01-01 – 2019-12-31	2026Q3
Lead (PB90)	0.001 mg/L	2014-01-01 – 2016-12-31	2026Q3
Lead (PB90)	0 mg/L	2011-01-01 – 2013-12-31	2026Q3
Lead (PB90)	0.001 mg/L	2008-01-01 – 2010-12-31	2026Q3

Twelve most recent imported state laboratory records
Substance	Published result	Sample date	Location / source
MANGANESE	< 2.000000000 UG/L	2026-07-13	GOLDMEDAL TREATMENT PLANT EFFLUENT / California DDW laboratory results
COLOR	2.0 UNITS	2026-07-06	SW23-TURBIDITY, COLOR, ODOR & MN / California DDW laboratory results
TURBIDITY	0.15 NTU	2026-07-06	SW21-TURBIDITY, COLOR, ODOR & MN / California DDW laboratory results
MANGANESE	30 UG/L	2026-07-06	BELHAVEN WELL 04 / California DDW laboratory results
COLOR	2.0 UNITS	2026-07-06	DBPR Sample / California DDW laboratory results
MANGANESE	12 UG/L	2026-07-06	DALTON WELL 02 / California DDW laboratory results
ODOR	< 1.000000000 TON	2026-07-06	SW4-TURBIDITY, COLOR, ODOR & MN / California DDW laboratory results
COLOR	< 2.000000000 UNITS	2026-07-06	SW48-TURBIDITY, COLOR, ODOR & MN / California DDW laboratory results
MANGANESE	31 UG/L	2026-07-06	BALLONA WELL 05 / California DDW laboratory results
MANGANESE	< 2.000000000 UG/L	2026-07-06	SOUTHERN WELL 05-PLANT EFFLUENT / California DDW laboratory results
ODOR	< 1.000000000 TON	2026-07-06	DBPR Sample / California DDW laboratory results
ODOR	2.0 TON	2026-07-06	SW51-TURBIDITY, COLOR, ODOR & MN / California DDW laboratory results

State sampling points can include untreated water. Publisher qualifiers and units are retained; consult the full source notes before interpreting a record.

Download state records with source notes (CSV)

Published compliance history

0 imported records. Status is as recorded in the source; historical records are not current advisories. Missing records do not establish that no violations occurred.

Source dates and refresh checks

A refresh check is not a sample date. Publication periods, sample dates and checks are shown separately.

EPA SDWIS lead/copper summaries and service areas — source period: — – —; last checked: 2026-10-17
EPA SDWIS contacts and compliance records — source period: — – —; last checked: 2026-10-17
EPA UCMR 5 sample results — source period: 2023-01-03 – 2026-06-17; last checked: 2026-10-17
California DDW laboratory results — last successful check: 2026-10-17

Administrative contact (EPA filing)

Schultise, Dave: 310-263-4141

An administrative filing contact may not be a customer-service line. Confirm current contact details with the provider.

Official state resources · How to read these records