Serving roughly 10,747 people in Los Angeles County, California.
Data current as of July 2026
🔍Straight from EPA
🧪Real Lab Results
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Results for GSWC - WILLOWBROOK
1 water provider directly on file, serving roughly 10,747 people in Los Angeles County, California.
Quick answer: GSWC - WILLOWBROOK has no violations on file and no single reading stands out against its peers (601 other providers in this area). It serves roughly 10,747 people, and the full breakdown below reflects everything EPA and California have on record for it.
Lead Summary
Lithium
TTHM
Bromoform
Bromodichloromethane
Dibromochloromethane
Copper, Free
Fluoride
Combined Uranium
Chromium, Hex
Utility GSWC - WILLOWBROOKPopulation served 10,747Owner Private
No violations on file
Contaminants found
Metals
Naturally occurring or corrosion-related elements, e.g. lead, arsenic, copper
Lead Summary
Detected: 0 mg/L (ppm)
12/31/2025
Copper, Free
Detected: 80 UG/L (ppb)
8/14/2025
Combined Uranium
Detected: 3.4 PCI/L
2/11/2025
A naturally occurring radioactive metal. Long-term exposure above the legal limit is associated with kidney effects and increased cancer risk.
Chromium, Hex
Detected: 0.52 UG/L (ppb)
2/11/2025
Disinfection Byproducts
Formed when chlorine used to disinfect water reacts with organic matter
TTHM
Detected: 8.1 UG/L (ppb)
8/5/2025
A group of disinfection byproducts formed when chlorine reacts with organic matter. Long-term exposure above the legal limit has been linked to increased cancer risk in some studies.
Bromoform
Detected: 2.5 UG/L (ppb)
8/5/2025
Bromodichloromethane
Detected: 1.7 UG/L (ppb)
8/5/2025
Dibromochloromethane
Detected: 3.2 UG/L (ppb)
8/5/2025
Inorganics
Common dissolved minerals and salts, e.g. nitrate, fluoride, chloride
Fluoride
Detected: 0.4 MG/L (ppm)
2/3/2025
Often added deliberately for dental health; can also occur naturally.
PFAS & Emerging Contaminants
Human-made "forever chemicals" and other substances not yet fully regulated
Lithium
Detected: 42 µg/L (ppb)
7/29/2024
Occurs naturally in some groundwater. Not currently federally regulated in drinking water.
Filtration considerations: See the table below for how whole-house carbon, under-sink reverse osmosis, and under-sink carbon systems compare against what's actually on file here. These are general system types, not a specific product recommendation.