MyTapWater.us

PWSID CA1910155

GSWC - SOUTHWEST

Community water system based in Hawthorne, CA

Service area on file with EPA: Los Angeles County. EPA's recorded service area can be incomplete for regional authorities. The cities and counties above are what the utility has filed with EPA; the utility may serve additional areas.

Population served
278k
Source
Surface water
Status
Active

At a glance

1 issue above the federal safety limit

Risk classification follows EPA's published values for safe drinking water, with caution and concern bands reviewed by a clinician. Past resolved violations do not influence this card. See methodology.

Lead service line inventory

Utility reports no confirmed lead service lines

GSWC - SOUTHWEST reports 0 confirmed lead service lines, 53,883 non-lead, 0 unknown (total 53,883) in the EPA SDWIS service line inventory (2026Q1).

  • 0 confirmed lead service lines
  • 0 galvanized requiring replacement (LCRI treats these as lead)
  • 0 unknown (0.0% of total)
  • 53,883 confirmed non-lead (100.0%)
  • 53,883 total service lines in the system
What to do if your service line might be lead
  1. Ask your utility to check the service-line classification for your specific address. Many utilities provide a public address-lookup tool linked from the inventory page.
  2. Get on the replacement queue. Under the LCRI, utilities must replace all lead and galvanized-requiring- replacement lines within 10 years (clock generally starts November 2027). Some prioritize requests.
  3. Until the line is replaced: flush the tap 30 seconds after long stagnation, use cold water for drinking and cooking, and consider an NSF/ANSI 53 lead-rated tap filter.
  4. Talk to your clinician about a blood lead test for anyone in the home, especially a pregnant person or a child under 6. Lead in drinking water guide.

Inventory data sourced from GSWC - SOUTHWEST ( retrieved May 24, 2026 ; curator confidence: high ). Confirmed against the original source automatically each month; see methodology.

Lead and copper test results

The most recent measurement per contaminant from EPA's Lead and Copper Rule sampling.

Why only lead and copper, and not arsenic, nitrate, or others?

EPA's bulk SDWIS download is the only nationwide per-system sample data they publish, and it only includes the Lead and Copper Rule table. Values for other regulated contaminants (TTHMs, nitrate, arsenic, etc.) appear on this page only when they trigger a violation. For the full per-system contaminant suite, see the utility's annual Consumer Confidence Report (link further down the page).

No recent Lead and Copper sample data

EPA's national SDWIS bulk dataset does not include Lead and Copper Rule sampling rows for this system in the most recent release. That can mean the system is small enough to be on a reduced sampling schedule, or that recent samples have not yet been submitted to EPA. Check the system's annual Consumer Confidence Report (see below) for the most recent local measurements.

Data from EPA SDWIS (Lead and Copper Rule sample table) , last refreshed May 24, 2026.

PFAS and emerging contaminants

This system was tested 540 times under EPA's latest PFAS monitoring program; 1 of the 30 chemicals tested was detected.

What is this testing program?

EPA's fifth Unregulated Contaminant Monitoring Rule cycle (UCMR 5, 2023 to 2025) required every public water system serving over 3,300 people to test for 29 per- and polyfluoroalkyl substances (PFAS) plus lithium; 30 chemicals in total. Most recent detection per chemical shown below.

Most recent UCMR 5 detection per contaminant . Sorted by risk: concern first, then caution, then unrated, then safe.
Contaminant Most recent detection Date Risk
lithium
0.0446 mg/LMarch 10, 2025 Concern
Tested but not detected (29 contaminants)

EPA tested for these substances and every sample was below the minimum reporting level. Absence of detection does not mean true zero; it means below the laboratory's quantitation threshold.

Data from EPA UCMR 5 (Unregulated Contaminant Monitoring Rule) , last refreshed May 24, 2026.

Fluoride

Per CDC My Water's Fluoride

GSWC - SOUTHWEST adds fluoride to its drinking water.

CDC classifies a system as fluoridated when it adjusts fluoride to the recommended level, or when it buys water from a system that does. The U.S. Public Health Service recommends 0.7 mg/L for community water fluoridation.

Source: CDC My Water's Fluoride, listed under Gswc - Southwest (Los Angeles County). Verify on CDC's site .

Area context

Los Angeles County, CA (2020 data)

Community water systems
81 of 200 add fluoride
Population on fluoridated water
3,153,498 of 4,634,852 (68.0%)

California statewide (2020 data)

Population on fluoridated water
21,879,582 of 38,051,212 (57.5%)
Community water systems adding fluoride
417 of 3,057

Data from CDC My Water's Fluoride (per-system status) , last refreshed May 19, 2026.

Data from CDC Water Fluoridation Reporting System (state and county aggregates) , last refreshed May 16, 2026.

Compliance history

EPA-recorded violations against this system over the last 5 years.

How to read this section

Health-based violations are when a measured limit was exceeded; the measured concentration is shown alongside the EPA federal limit where SDWIS published it. Monitoring and reporting items are paperwork issues (missed sample dates, late filings) that do not themselves indicate unsafe water.

Clean record

No violations on file for this system in the last 5 years.

Data from EPA SDWIS (violation records) , last refreshed May 24, 2026.

Where to see every contaminant this utility tested for

EPA's bulk SDWIS dataset gives MyTapWater.us per-system measured values for lead and copper, plus violation records for everything else. To see every regulated contaminant this utility tested for in the past year (TTHMs, HAA5, nitrate, arsenic, fluoride, chromium, etc.) with measured values, read the utility's Consumer Confidence Report (CCR).

Every community water system is required by EPA to publish a CCR annually, by July 1, listing every contaminant they sampled, the measured value, the federal limit, and any health-based exceedances. Most utilities post the report online; some mail it with your bill.

How to find GSWC - SOUTHWEST's CCR:

Other water systems in Los Angeles County, CA

Compare nearby utilities by population served.

Contact this utility

Public administrative contact information for this water system, as filed with the EPA. Use this to ask about your service line, request your home's lead status, or report a water quality issue.

Administrator
SCHULTISE, DAVE
Phone
310-263-4141 x110
Email
David.Schultise@gswater.com
Mailing address
14401 SOUTH CHADRON AVENUE
HAWTHORNE, CA 90250

Where this page's data comes from

Bundle released 2026-Q2, regenerated May 24, 2026. Each section above also shows its own source date so you can tell at a glance how fresh that part of the page is.

Every value on this page is cross-verified before publication; read our methodology for the verification steps and corrections process.