whatsinmywater.co
EPA SDWIS · Riverside County, California

LAKE HEMET MWD Water Quality Report

Serving roughly 52,913 people in Riverside County, California.

Data current as of July 2026
🔍Straight from EPA
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Results for LAKE HEMET MWD

1 water provider directly on file, serving roughly 52,913 people in Riverside County, California.

Quick answer: LAKE HEMET MWD has no violations on file. One reading is worth knowing about: Bromodichloromethane was measured at 12.8UG/L, 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.
Utility LAKE HEMET MWD Population served 52,913 Owner Local government
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
Manganese
Detected: 7 UG/L (ppb)
8/7/2025
Mainly a taste/staining concern at typical levels; long-term neurological research at high chronic exposure is ongoing.
Chromium, Hex
Detected: 0.13 UG/L (ppb)
10/1/2025
Copper, Free
Detected: 210 UG/L (ppb)
8/27/2025
Zinc
Detected: 5.2 UG/L (ppb)
8/7/2025
Vanadium, Total
Detected: 67 UG/L (ppb)
8/6/2025
Arsenic
Detected: 7 UG/L (ppb)
8/6/2025
Occurs naturally in some groundwater. Long-term exposure above the legal limit (10 ppb) has been linked to increased cancer risk and cardiovascular disease.
Disinfection Byproducts
Formed when chlorine used to disinfect water reacts with organic matter
TTHM
Detected: 2.2 UG/L (ppb)
8/6/2025
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: 1.2 UG/L (ppb)
8/6/2025
Totalhaloaceticacids (HAA5)
Detected: 6 UG/L (ppb)
2/5/2025
Chloroform
Detected: 7 UG/L (ppb)
2/5/2025
One of the individual trihalomethane disinfection byproducts, formed when chlorine reacts with organic matter.
Bromodichloromethane
Detected: 12.8 UG/L (ppb)
2/5/2025
Dibromochloromethane
Detected: 13 UG/L (ppb)
2/5/2025
Inorganics
Common dissolved minerals and salts, e.g. nitrate, fluoride, chloride
Chloride
Detected: 29.8 MG/L (ppm)
8/7/2025
Sulfate
Detected: 64.4 MG/L (ppm)
8/7/2025
Fluoride
Detected: 0.19 MG/L (ppm)
8/7/2025
Often added deliberately for dental health; can also occur naturally.
Nitrate
Detected: 1.5 MG/L (ppm)
10/1/2025
Commonly from agricultural fertilizer runoff or septic systems. Above the legal limit, it's an immediate concern especially for infants.
Boron, Total
Detected: 65 UG/L (ppb)
8/7/2025
Minerals
Everyday minerals that mainly affect taste and water hardness
Magnesium
Detected: 5.45 MG/L (ppm)
8/7/2025
Calcium
Detected: 51.1 MG/L (ppm)
8/7/2025
Potassium
Detected: 4.6 MG/L (ppm)
8/7/2025
Sodium
Detected: 38.6 MG/L (ppm)
8/7/2025
Properties
General water characteristics like pH, hardness, and cloudiness (turbidity)
Hardness, Total (ASCACO3)
Detected: 150 MG/L (ppm)
8/7/2025
PFAS & Emerging Contaminants
Human-made "forever chemicals" and other substances not yet fully regulated
Lithium
Detected: 10.9 µg/L (ppb)
10/21/2024
Occurs naturally in some groundwater. Not currently federally regulated in drinking water.
Calculated Parameters
Values worked out mathematically from other test results, not measured directly
Alkalinity, Bicarbonate
Detected: 135 MG/L (ppm)
8/7/2025
Other
Additional substances tested that don't fit neatly into the categories above
Silica
Detected: 23.3 MG/L (ppm)
8/7/2025
Alkalinity, Total
Detected: 111 MG/L (ppm)
8/7/2025
Carbon, Total
Detected: 0.34 MG/L (ppm)
8/7/2025
TDS
Detected: 306 MG/L (ppm)
8/7/2025
Radium-228
Detected: 0.134 PCI/L
9/5/2025
Conductivity (at 25°C)
Detected: 486 UMHO/CM
8/7/2025
Dichloroaceticacid
Detected: 2.6 UG/L (ppb)
2/5/2025
Trichloroaceticacid
Detected: 1.3 UG/L (ppb)
2/5/2025
Dibromoaceticacid
Detected: 2.1 UG/L (ppb)
2/5/2025
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.
Contaminant Whole-House Carbon Under-Sink RO Under-Sink Carbon
Total Trihalomethanes (TTHM)YesYesYes
Haloacetic Acids (HAA5)YesYesYes
ChloroformYesYesYes
Chlorine / TasteYesYesYes
Sediment / TurbidityYesYesYes
TrichloroethyleneYesYesYes
TetrachloroethyleneYesYesYes
cis-1,2-DichloroethyleneYesYesYes
1,1-DichloroethyleneYesYesYes
BromoformYesYesYes
BromodichloromethaneYesYesYes
DibromochloromethaneYesYesYes
1,1,2-TrichloroethaneYesYesYes
Vinyl ChlorideYesYesYes
Carbon TetrachlorideYesYesYes
BenzeneYesYesYes
TolueneYesYesYes
XyleneYesYesYes
Totalhaloaceticacids (HAA5)YesYesYes
LeadPartialYesPartial
ArsenicPartialYesPartial
Chromium-6 (Hexavalent)PartialYesPartial
CopperPartialYesPartial
Combined UraniumPartialYesPartial
PFOAPartialYes*Partial
PFOSPartialYes*Partial
NitratePartialYesPartial
Combined RadiumPartialYesPartial
LithiumPartialYes*Partial
SilicaPartialYesPartial
Alkalinity, TotalPartialYesPartial
Carbon, TotalPartialYesPartial
TDSPartialYesPartial
ChloridePartialYesPartial
SulfatePartialYesPartial
FluoridePartialYesPartial
Boron, TotalPartialYesPartial
ManganesePartialYesPartial
Chromium, HexPartialYesPartial
Copper, FreePartialYesPartial
ZincPartialYesPartial
Conductivity (at 25°C)PartialYesPartial
DichloroaceticacidPartialYesPartial
TrichloroaceticacidPartialYesPartial
DibromoaceticacidPartialYesPartial
Vanadium, TotalPartialYesPartial
Coliform Bacteria (indicator)NoYesNo
MagnesiumNoPartialNo
CalciumNoPartialNo
PotassiumNoPartialNo
SodiumNoPartialNo
Hardness, Total (ASCACO3)NoNoNo
Alkalinity, BicarbonateNoNoNo

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What is TTHM? Understanding EPA Violation Status Is Chromium-6 Dangerous? Whole-House vs. Under-Sink Filtration Lead and Copper in Drinking Water What is PFAS? Arsenic and Uranium Explained Nitrate and Fluoride Explained Water Hardness, pH, and Turbidity What is Coliform Bacteria?