Serving roughly 86,062 people in Riverside County, California.
Data current as of July 2026
🔍Straight from EPA
🧪Real Lab Results
📅Updated Quarterly
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Results for WESTERN MWD
1 water provider directly on file, serving roughly 86,062 people in Riverside County, California.
Quick answer: WESTERN MWD has no violations on file. One reading is worth knowing about: pH was measured at 8.6PH, among the highest of the 451 providers on file in this area. It's the most notable figure in this system's record among its 451 local peers.
Lead Summary
Lithium
PFHXS
PFBS
PFPEA
Fluoride
Nitrate
Perfluoroctanesulfonicacid (PFOS)
Perfluorohexanoicacid (PFHXA)
Perfluorobutanoicacid (PFBA)
Perfluoropentanoicacid (PFPEA)
pH
TTHM
Totalhaloaceticacids (HAA5)
Lead
Bromoform
Bromodichloromethane
Dibromochloromethane
Chloroform
Dichloroaceticacid
Dibromoaceticacid
Copper, Free
Utility WESTERN MWDPopulation served 86,062Owner Local government
No violations on file
Contaminants found
Metals
Naturally occurring or corrosion-related elements, e.g. lead, arsenic, copper
Lead Summary
Detected: 0.0013 mg/L (ppm)
12/31/2025
Lead
Detected: 3.2 UG/L (ppb)
8/9/2025
A metal that can leach from old pipes, solder, and fixtures. Current medical guidance holds there is no truly safe level of lead exposure, especially for children and pregnant women.
Copper, Free
Detected: 170 UG/L (ppb)
8/9/2025
Disinfection Byproducts
Formed when chlorine used to disinfect water reacts with organic matter
TTHM
Detected: 4 UG/L (ppb)
5/7/2025
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.
Totalhaloaceticacids (HAA5)
Detected: 6.1 UG/L (ppb)
5/7/2025
Bromoform
Detected: 1.7 UG/L (ppb)
5/7/2025
Bromodichloromethane
Detected: 0.78 UG/L (ppb)
5/7/2025
Dibromochloromethane
Detected: 1.5 UG/L (ppb)
5/7/2025
Chloroform
Detected: 5.6 UG/L (ppb)
5/7/2025
One of the individual trihalomethane disinfection byproducts, formed when chlorine reacts with organic matter.
Inorganics
Common dissolved minerals and salts, e.g. nitrate, fluoride, chloride
Fluoride
Detected: 0.62 MG/L (ppm)
8/7/2025
Often added deliberately for dental health; can also occur naturally.
Nitrate
Detected: 0.28 MG/L (ppm)
6/10/2025
Commonly from agricultural fertilizer runoff or septic systems. Above the legal limit, it's an immediate concern especially for infants.
Properties
General water characteristics like pH, hardness, and cloudiness (turbidity)
pH
Detected: 8.6 PH
9/4/2025
A measure of how acidic or basic the water is (7 is neutral). Affects taste and plumbing, not a direct health measure.
PFAS & Emerging Contaminants
Human-made "forever chemicals" and other substances not yet fully regulated
Lithium
Detected: 16 µg/L (ppb)
9/14/2023
Occurs naturally in some groundwater. Not currently federally regulated in drinking water.
PFHXS
Detected: 0.0034 µg/L (ppb)
9/14/2023
PFBS
Detected: 0.003 µg/L (ppb)
9/14/2023
PFPEA
Detected: 0.0047 µg/L (ppb)
12/13/2023
Other
Additional substances tested that don't fit neatly into the categories above
Perfluoroctanesulfonicacid (PFOS)
Detected: 1.7 NG/L (ppt)
5/7/2025
One of two PFAS with an enforceable federal limit (4 ppt) since 2024.
Perfluorohexanoicacid (PFHXA)
Detected: 3.1 NG/L (ppt)
5/7/2025
Perfluorobutanoicacid (PFBA)
Detected: 3.6 NG/L (ppt)
5/7/2025
Perfluoropentanoicacid (PFPEA)
Detected: 5.9 NG/L (ppt)
5/7/2025
Dichloroaceticacid
Detected: 3.8 UG/L (ppb)
5/7/2025
Dibromoaceticacid
Detected: 2.3 UG/L (ppb)
5/7/2025
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.