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Water Quality Lookup / California / Los Angeles County
EPA SDWIS Β· Los Angeles County, California Β· 601 providers profiled

Los Angeles County, CA Water Quality Report

Los Angeles County is served by 601 major public water systems on file with the EPA.

Data current as of July 2026
πŸ”Straight from EPA
πŸ§ͺReal Lab Results
πŸ“…Updated Quarterly
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Results for Los Angeles County, CA

601 water providers on file for this county, sorted by population served.

Quick answer: Los Angeles County has 601 water providers profiled, sorted by population served.

Violations on file

Coliform (TCR)
Older/archived health-based violation
Found at 21 of 601 providers
Fluoride
Older/archived health-based violation
Found at 7 of 601 providers
Often added deliberately for dental health; can also occur naturally.
Nitrate
Older/archived health-based violation
Found at 9 of 601 providers
Commonly from agricultural fertilizer runoff or septic systems. Above the legal limit, it's an immediate concern especially for infants.
Selenium
Older/archived health-based violation
Found at 1 of 601 providers
Arsenic
Older/archived health-based violation
Found at 10 of 601 providers
Occurs naturally in some groundwater. Long-term exposure above the legal limit (10 ppb) has been linked to increased cancer risk and cardiovascular disease.
Lead And Copper Rule Revisions
Currently open health violation
Found at 23 of 601 providers
Surface Water Treatment Rule
Currently open health violation
Found at 2 of 601 providers

Contaminants found

Metals
Naturally occurring or corrosion-related elements, e.g. lead, arsenic, copper
Lead Summary
Detected: 0.054 mg/L (ppm)
Found at 230 providers
Copper, Free
Detected: 830 UG/L (ppb)
Found at 72 providers
Copper Summary
Detected: 5.6 mg/L (ppm)
Found at 12 providers
Combined Uranium
Detected: 19 PCI/L
Found at 38 providers
A naturally occurring radioactive metal. Long-term exposure above the legal limit is associated with kidney effects and increased cancer risk.
Chromium, Hex
Detected: 17 UG/L (ppb)
Found at 90 providers
Lead
Detected: 26 UG/L (ppb)
Found at 39 providers
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.
Arsenic
Detected: 71 UG/L (ppb)
Found at 44 providers
Occurs naturally in some groundwater. Long-term exposure above the legal limit (10 ppb) has been linked to increased cancer risk and cardiovascular disease.
Molybdenum, Total
Detected: 5.8 UG/L (ppb)
Found at 3 providers
Iron
Detected: 2380 UG/L (ppb)
Found at 35 providers
Mostly an aesthetic issue (metallic taste, staining) rather than a health concern at typical levels.
Nickel
Detected: 2.8 UG/L (ppb)
Found at 5 providers
Chromium
Detected: 27 UG/L (ppb)
Found at 13 providers
Occurs in two forms β€” trivalent (an essential nutrient in trace amounts) and hexavalent (linked to increased cancer risk).
Barium
Detected: 170 UG/L (ppb)
Found at 28 providers
Selenium
Detected: 16 UG/L (ppb)
Found at 3 providers
Zinc
Detected: 626 UG/L (ppb)
Found at 14 providers
Manganese
Detected: 200 UG/L (ppb)
Found at 39 providers
Mainly a taste/staining concern at typical levels; long-term neurological research at high chronic exposure is ongoing.
Vanadium, Total
Detected: 18 UG/L (ppb)
Found at 9 providers
Aluminum
Detected: 110 UG/L (ppb)
Found at 7 providers
Thallium, Total
Detected: 1.2 UG/L (ppb)
6/17/2025
Strontium
Detected: 430 UG/L (ppb)
6/10/2025
38-Strontium-90
Detected: 0.611 PCI/L
2/19/2025
Disinfection Byproducts
Formed when chlorine used to disinfect water reacts with organic matter
TTHM
Detected: 82 UG/L (ppb)
Found at 141 providers
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.
Chloroform
Detected: 46.9 UG/L (ppb)
Found at 124 providers
One of the individual trihalomethane disinfection byproducts, formed when chlorine reacts with organic matter.
Dibromochloromethane
Detected: 30 UG/L (ppb)
Found at 138 providers
Bromoform
Detected: 33 UG/L (ppb)
Found at 128 providers
Bromodichloromethane
Detected: 42 UG/L (ppb)
Found at 128 providers
Totalhaloaceticacids (HAA5)
Detected: 42 UG/L (ppb)
Found at 93 providers
Bromochloromethane
Detected: 1.2 UG/L (ppb)
1/22/2025
Dibromomethane
Detected: 0.71 UG/L (ppb)
1/22/2025
Inorganics
Common dissolved minerals and salts, e.g. nitrate, fluoride, chloride
Nitrate-Nitrite
Detected: 20 MG/L (ppm)
Found at 38 providers
Nitrate
Detected: 20 MG/L (ppm)
Found at 174 providers
Commonly from agricultural fertilizer runoff or septic systems. Above the legal limit, it's an immediate concern especially for infants.
Fluoride
Detected: 2.2 MG/L (ppm)
Found at 83 providers
Often added deliberately for dental health; can also occur naturally.
Sulfate
Detected: 510 MG/L (ppm)
Found at 79 providers
Chloride
Detected: 280 MG/L (ppm)
Found at 75 providers
Boron, Total
Detected: 4000 UG/L (ppb)
Found at 19 providers
Nitrite
Detected: 0.84 MG/L (ppm)
Found at 3 providers
Minerals
Everyday minerals that mainly affect taste and water hardness
Magnesium
Detected: 62 MG/L (ppm)
Found at 70 providers
Potassium
Detected: 9.3 MG/L (ppm)
Found at 58 providers
Sodium
Detected: 150 MG/L (ppm)
Found at 63 providers
Calcium
Detected: 144 MG/L (ppm)
Found at 75 providers
Properties
General water characteristics like pH, hardness, and cloudiness (turbidity)
Gross Alpha Particle Activity
Detected: 14.9 PCI/L
Found at 28 providers
Hardness, Total (ASCACO3)
Detected: 540 MG/L (ppm)
Found at 64 providers
pH
Detected: 8.6 PH
Found at 50 providers
A measure of how acidic or basic the water is (7 is neutral). Affects taste and plumbing, not a direct health measure.
Langelier Index (pH(s))
Detected: 1.8 LANG
Found at 27 providers
N-Nitrosomorpholine (NMOR)
Detected: 0.0065 UG/L (ppb)
Found at 3 providers
pH, Field
Detected: 8.41 PH
Found at 19 providers
Orthophosphate
Detected: 1 MG/L (ppm)
Found at 5 providers
Phosphate, Total
Detected: 40 UG/L (ppb)
8/27/2025
PFAS & Emerging Contaminants
Human-made "forever chemicals" and other substances not yet fully regulated
Lithium
Detected: 91.9 Β΅g/L (ppb)
Found at 71 providers
Occurs naturally in some groundwater. Not currently federally regulated in drinking water.
PFHXS
Detected: 0.011 Β΅g/L (ppb)
Found at 41 providers
PFHXA
Detected: 0.021 Β΅g/L (ppb)
Found at 31 providers
PFPEA
Detected: 0.0376 Β΅g/L (ppb)
Found at 35 providers
PFBA
Detected: 0.0221 Β΅g/L (ppb)
Found at 32 providers
PFOA
Detected: 0.0169 Β΅g/L (ppb)
Found at 39 providers
One of two PFAS with an enforceable federal limit (4 ppt) since 2024.
PFOS
Detected: 0.053 Β΅g/L (ppb)
Found at 47 providers
One of two PFAS with an enforceable federal limit (4 ppt) since 2024.
PFHPA
Detected: 0.0064 Β΅g/L (ppb)
Found at 15 providers
PFBS
Detected: 0.0647 Β΅g/L (ppb)
Found at 28 providers
Pfda
Detected: 0.0051 Β΅g/L (ppb)
Found at 3 providers
Pfpes
Detected: 0.0245 Β΅g/L (ppb)
9/9/2025
VOCs (Volatile Organic Compounds)
Industrial solvents and fuel-related chemicals that evaporate easily
1, 2, 3-Trichloropropane
Detected: 0.16 UG/L (ppb)
Found at 5 providers
Trichloroethylene
Detected: 84 UG/L (ppb)
Found at 37 providers
Tetrachloroethylene
Detected: 110 UG/L (ppb)
Found at 34 providers
Styrene
Detected: 2 UG/L (ppb)
Found at 4 providers
Dichloromethane
Detected: 1.2 UG/L (ppb)
Found at 3 providers
Cis-1, 2-Dichloroethylene
Detected: 3.4 UG/L (ppb)
Found at 7 providers
1, 1-Dichloroethylene
Detected: 2.9 UG/L (ppb)
Found at 11 providers
1, 1, 2-Trichloroethane
Detected: 0.5 UG/L (ppb)
7/28/2025
Carbontetrachloride
Detected: 7.8 UG/L (ppb)
Found at 7 providers
Bromide
Detected: 0.81 MG/L (ppm)
Found at 3 providers
Chloromethane
Detected: 0.59 UG/L (ppb)
Found at 3 providers
1, 2, 3-Trichlorobenzene
Detected: 0.72 UG/L (ppb)
1/10/2025
1, 2, 4-Trichlorobenzene
Detected: 0.67 UG/L (ppb)
1/10/2025
Dichlorodifluoromethane
Detected: 2.5 UG/L (ppb)
Found at 3 providers
1, 2-Dichloroethane
Detected: 11 UG/L (ppb)
Found at 4 providers
Vinylchloride
Detected: 1.9 UG/L (ppb)
4/10/2025
Chlorobenzene
Detected: 2.3 UG/L (ppb)
4/10/2025
1, 2-Dichloropropane
Detected: 0.94 UG/L (ppb)
2/2/2025
Petroleum Compounds
Substances associated with fuel or petroleum contamination
O-Xylene
Detected: 7.2 UG/L (ppb)
Found at 3 providers
Xylene, Metaandpara
Detected: 2.1 UG/L (ppb)
Found at 5 providers
Benzene
Detected: 22 UG/L (ppb)
Found at 5 providers
Toluene
Detected: 28.5 UG/L (ppb)
Found at 4 providers
Ethylbenzene
Detected: 6 UG/L (ppb)
Found at 4 providers
Naphthalene
Detected: 1.3 UG/L (ppb)
Found at 2 providers
Xylenes, Total
Detected: 1 UG/L (ppb)
Found at 6 providers
O-Dichlorobenzene
Detected: 0.5 UG/L (ppb)
4/10/2025
Calculated Parameters
Values worked out mathematically from other test results, not measured directly
Alkalinity, Bicarbonate
Detected: 440 MG/L (ppm)
Found at 70 providers
Alkalinity, Carbonate
Detected: 10 MG/L (ppm)
Found at 3 providers
Other
Additional substances tested that don't fit neatly into the categories above
Dichloroaceticacid
Detected: 22.4 UG/L (ppb)
Found at 94 providers
Dibromoaceticacid
Detected: 29 UG/L (ppb)
Found at 110 providers
Trichloroaceticacid
Detected: 10.4 UG/L (ppb)
Found at 77 providers
Alkalinity, Total
Detected: 380 MG/L (ppm)
Found at 77 providers
Carbon, Total
Detected: 3.22 MG/L (ppm)
Found at 16 providers
Monochloroaceticacid
Detected: 9 UG/L (ppb)
Found at 11 providers
Perchlorate
Detected: 14 UG/L (ppb)
Found at 32 providers
Can occur naturally or from industrial/military sources; may interfere with thyroid function at elevated levels.
Conductivity (at 25Β°C)
Detected: 1530 UMHO/CM
Found at 49 providers
TDS
Detected: 1200 MG/L (ppm)
Found at 76 providers
Foamingagents (SURFACTANTS)
Detected: 0.19 MG/L (ppm)
Found at 8 providers
Radium-228
Detected: 1.91 PCI/L
Found at 15 providers
Perfluorobutanesulfonicacid (PFBS)
Detected: 540 NG/L (ppt)
Found at 35 providers
Perfluorohexanesulfonicacid (PFHxS)
Detected: 9.1 NG/L (ppt)
Found at 50 providers
Perfluorobutanoicacid (PFBA)
Detected: 15 NG/L (ppt)
Found at 50 providers
Perfluoropentanoicacid (PFPEA)
Detected: 19 NG/L (ppt)
Found at 38 providers
Turbidity
Detected: 11 NTU
Found at 65 providers
A measure of water cloudiness from suspended particles.
Radium-226
Detected: 0.58 PCI/L
Found at 4 providers
1, 4-Dioxane
Detected: 4.7 UG/L (ppb)
Found at 23 providers
Methyltert-Butylether
Detected: 0.57 UG/L (ppb)
8/25/2025
Aggressive Index
Detected: 13 AGGR
Found at 41 providers
Perfluoroctanesulfonicacid (PFOS)
Detected: 61 NG/L (ppt)
Found at 50 providers
One of two PFAS with an enforceable federal limit (4 ppt) since 2024.
Perfluoroctanoicacid (PFOA)
Detected: 17 NG/L (ppt)
Found at 49 providers
One of two PFAS with an enforceable federal limit (4 ppt) since 2024.
Odor
Detected: 35 TON
Found at 34 providers
Color
Detected: 15 UNITS
Found at 14 providers
Perfluoroheptanoicacid (PFHPA)
Detected: 10 NG/L (ppt)
Found at 30 providers
Perfluorononanoicacid (PFNA)
Detected: 5.1 NG/L (ppt)
Found at 16 providers
Perfluorohexanoicacid (PFHXA)
Detected: 19 NG/L (ppt)
Found at 42 providers
Perfluorodecanoicacid (PFDA)
Detected: 6 NG/L (ppt)
Found at 10 providers
Carbondioxide
Detected: 38000 UG/L (ppb)
Found at 2 providers
Temperature (CENTIGRADE)
Detected: 26.9 C
Found at 11 providers
Sulfide
Detected: 0.2 MG/L (ppm)
10/15/2025
Adsorbableorganicfluorine
Detected: 5300 NG/L (ppt)
Found at 8 providers
Perfluoropentanesulfonicacid (PFPES)
Detected: 8.4 NG/L (ppt)
Found at 6 providers
Nitrogen-Ammoniaas (N)
Detected: 1.3 MG/L (ppm)
Found at 2 providers
Methylethylketone
Detected: 11 UG/L (ppb)
Found at 2 providers
Langelier Index (Source Temp.)
Detected: 1.2 LANG
Found at 16 providers
Gross Beta Particle Activity
Detected: 6.63 PCI/L
Found at 4 providers
Monobromoaceticacid
Detected: 2.5 UG/L (ppb)
Found at 19 providers
N-Nitrosodimethylamine
Detected: 0.004 UG/L (ppb)
Found at 4 providers
Carbondisulfide
Detected: 1.2 UG/L (ppb)
1/19/2025
Perfluorooctanesulfonicacid6:2fts
Detected: 7.8 NG/L (ppt)
3/4/2025
Combined Radium (-226 & -228)
Detected: 0.776 PCI/L
9/8/2025
A naturally occurring radioactive element found in some groundwater.
TotalradiumforntncperΒ§64442(B) (3)
Detected: 0.4 PCI/L
1/14/2025
Simazine
Detected: 0.049 UG/L (ppb)
7/17/2025
Bromate
Detected: 2.5 UG/L (ppb)
3/19/2025
Silica
Detected: 25 MG/L (ppm)
Found at 2 providers
Chlorate
Detected: 66.9 UG/L (ppb)
9/2/2025
Filtration considerations: 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
1, 2, 3-TrichloropropaneYesYesYes
Totalhaloaceticacids (HAA5)YesYesYes
StyreneYesYesYes
DichloromethaneYesYesYes
CarbontetrachlorideYesYesYes
BromideYesYesYes
ChloromethaneYesYesYes
1, 2, 3-TrichlorobenzeneYesYesYes
BromochloromethaneYesYesYes
DibromomethaneYesYesYes
1, 2, 4-TrichlorobenzeneYesYesYes
DichlorodifluoromethaneYesYesYes
1, 2-DichloroethaneYesYesYes
VinylchlorideYesYesYes
ChlorobenzeneYesYesYes
1, 2-DichloropropaneYesYesYes
LeadPartialYesPartial
ArsenicPartialYesPartial
Chromium-6 (Hexavalent)PartialYesPartial
CopperPartialYesPartial
Combined UraniumPartialYesPartial
PFOAPartialYes*Partial
PFOSPartialYes*Partial
NitratePartialYesPartial
Combined RadiumPartialYesPartial
Copper, FreePartialYesPartial
Nitrate-NitritePartialYesPartial
LithiumPartialYes*Partial
PFHXSPartialYes*Partial
PFHXAPartialYes*Partial
PFPEAPartialYes*Partial
PFBAPartialYes*Partial
PFHPAPartialYes*Partial
PFBSPartialYes*Partial
DichloroaceticacidPartialYesPartial
DibromoaceticacidPartialYesPartial
TrichloroaceticacidPartialYesPartial
FluoridePartialYesPartial
Combined UraniumPartialYesPartial
Chromium, HexPartialYesPartial
Alkalinity, TotalPartialYesPartial
Carbon, TotalPartialYesPartial
O-XylenePartialYesPartial
Xylene, MetaandparaPartialYesPartial
EthylbenzenePartialYesPartial
MonochloroaceticacidPartialYesPartial
SulfatePartialYesPartial
ChloridePartialYesPartial
PerchloratePartialYesPartial
Conductivity (at 25Β°C)PartialYesPartial
TDSPartialYesPartial
Foamingagents (SURFACTANTS)PartialYesPartial
Perfluorobutanesulfonicacid (PFBS)PartialYesPartial
Perfluorohexanesulfonicacid (PFHxS)PartialYesPartial
Perfluorobutanoicacid (PFBA)PartialYesPartial
Perfluoropentanoicacid (PFPEA)PartialYesPartial
Radium-226PartialYesPartial
Molybdenum, TotalPartialYesPartial
IronPartialYesPartial
NickelPartialYesPartial
ChromiumPartialYesPartial
BariumPartialYesPartial
SeleniumPartialYesPartial
ZincPartialYesPartial
1, 4-DioxanePartialYesPartial
Methyltert-ButyletherPartialYesPartial
ManganesePartialYesPartial
Aggressive IndexPartialYesPartial
Perfluoroctanesulfonicacid (PFOS)PartialYesPartial
Perfluoroctanoicacid (PFOA)PartialYesPartial
OdorPartialYesPartial
ColorPartialYesPartial
Perfluoroheptanoicacid (PFHPA)PartialYesPartial
Perfluorononanoicacid (PFNA)PartialYesPartial
Perfluorohexanoicacid (PFHXA)PartialYesPartial
PfdaPartialYes*Partial
Perfluorodecanoicacid (PFDA)PartialYesPartial
CarbondioxidePartialYesPartial
Temperature (CENTIGRADE)PartialYesPartial
SulfidePartialYesPartial
Boron, TotalPartialYesPartial
AdsorbableorganicfluorinePartialYesPartial
Perfluoropentanesulfonicacid (PFPES)PartialYesPartial
Nitrogen-Ammoniaas (N)PartialYesPartial
MethylethylketonePartialYesPartial
Langelier Index (Source Temp.)PartialYesPartial
Gross Beta Particle ActivityPartialYesPartial
Vanadium, TotalPartialYesPartial
MonobromoaceticacidPartialYesPartial
N-NitrosodimethylaminePartialYesPartial
NaphthalenePartialYesPartial
CarbondisulfidePartialYesPartial
Xylenes, TotalPartialYesPartial
Perfluorooctanesulfonicacid6:2ftsPartialYesPartial
AluminumPartialYesPartial
NitritePartialYesPartial
Thallium, TotalPartialYesPartial
Combined Radium (-226 & -228)PartialYesPartial
StrontiumPartialYesPartial
TotalradiumforntncperΒ§64442(B) (3)PartialYesPartial
SimazinePartialYesPartial
BromatePartialYesPartial
SilicaPartialYesPartial
O-DichlorobenzenePartialYesPartial
38-Strontium-90PartialYesPartial
PfpesPartialYes*Partial
ChloratePartialYesPartial
Coliform Bacteria (indicator)NoYesNo
Gross Alpha Particle ActivityNoNoNo
Alkalinity, BicarbonateNoNoNo
MagnesiumNoPartialNo
PotassiumNoPartialNo
SodiumNoPartialNo
Hardness, Total (ASCACO3)NoNoNo
CalciumNoPartialNo
pHNoNoNo
Langelier Index (pH(s))NoNoNo
Alkalinity, CarbonateNoNoNo
N-Nitrosomorpholine (NMOR)NoNoNo
pH, FieldNoNoNo
OrthophosphateNoNoNo
Phosphate, TotalNoNoNo

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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?