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Water Quality Lookup / California / San Diego County
EPA SDWIS ยท San Diego County, California ยท 414 providers profiled

San Diego County, CA Water Quality Report

San Diego County is served by 414 major public water systems on file with the EPA.

Data current as of July 2026
๐Ÿ”Straight from EPA
๐ŸงชReal Lab Results
๐Ÿ“…Updated Quarterly
๐Ÿ Local Expertise
Results for San Diego County, CA

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

Quick answer: San Diego County has 414 water providers profiled, sorted by population served.

Violations on file

Nitrate-Nitrite
Older/archived health-based violation
Found at 6 of 414 providers
Combined Uranium
Older/archived health-based violation
Found at 7 of 414 providers
A naturally occurring radioactive metal. Long-term exposure above the legal limit is associated with kidney effects and increased cancer risk.
Nitrate
Older/archived health-based violation
Found at 16 of 414 providers
Commonly from agricultural fertilizer runoff or septic systems. Above the legal limit, it's an immediate concern especially for infants.
Coliform (TCR)
Older/archived health-based violation
Found at 18 of 414 providers
Copper, Free
Older/archived health-based violation
Found at 1 of 414 providers
Fluoride
Older/archived health-based violation
Found at 11 of 414 providers
Often added deliberately for dental health; can also occur naturally.
Lead And Copper Rule Revisions
Currently open health violation
Found at 8 of 414 providers
Surface Water Treatment Rule
Currently open health violation
Found at 4 of 414 providers
TTHM
Older/archived health-based violation
Found at 1 of 414 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.
Total Haloacetic Acids (HAA5)
Older/archived health-based violation
Found at 1 of 414 providers
Arsenic
Older/archived health-based violation
Found at 2 of 414 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.
Selenium
Older/archived health-based violation
Found at 1 of 414 providers
Bromate
Older/archived health-based violation
Found at 1 of 414 providers
Revised Total Coliform Rule
Older/archived health-based violation
Found at 2 of 414 providers

Contaminants found

Metals
Naturally occurring or corrosion-related elements, e.g. lead, arsenic, copper
Lead Summary
Detected: 0.07 mg/L (ppm)
Found at 107 providers
Iron
Detected: 19000 UG/L (ppb)
Found at 33 providers
Mostly an aesthetic issue (metallic taste, staining) rather than a health concern at typical levels.
Manganese
Detected: 630 UG/L (ppb)
Found at 38 providers
Mainly a taste/staining concern at typical levels; long-term neurological research at high chronic exposure is ongoing.
Copper Summary
Detected: 177 mg/L (ppm)
Found at 11 providers
Chromium, Hex
Detected: 3.3 UG/L (ppb)
Found at 29 providers
Lead
Detected: 27 UG/L (ppb)
Found at 15 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.
Copper, Free
Detected: 980 UG/L (ppb)
Found at 33 providers
Combined Uranium
Detected: 161 PCI/L
Found at 30 providers
A naturally occurring radioactive metal. Long-term exposure above the legal limit is associated with kidney effects and increased cancer risk.
Chromium
Detected: 3.2 UG/L (ppb)
Found at 4 providers
Occurs in two forms โ€” trivalent (an essential nutrient in trace amounts) and hexavalent (linked to increased cancer risk).
Barium
Detected: 180 UG/L (ppb)
Found at 13 providers
Selenium
Detected: 180 UG/L (ppb)
Found at 8 providers
Aluminum
Detected: 3600 UG/L (ppb)
Found at 11 providers
Zinc
Detected: 310 UG/L (ppb)
Found at 13 providers
Vanadium, Total
Detected: 91.4 UG/L (ppb)
Found at 14 providers
Nickel
Detected: 20 UG/L (ppb)
Found at 4 providers
Molybdenum, Total
Detected: 0.62 UG/L (ppb)
9/24/2025
Arsenic
Detected: 21 UG/L (ppb)
Found at 16 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.
Iron, Dissolved
Detected: 8300 UG/L (ppb)
8/4/2025
38-Strontium-90
Detected: 1.38 PCI/L
4/4/2025
Silver
Detected: 0.23 UG/L (ppb)
6/10/2025
Disinfection Byproducts
Formed when chlorine used to disinfect water reacts with organic matter
Totalhaloaceticacids (HAA5)
Detected: 49.6 UG/L (ppb)
Found at 58 providers
TTHM
Detected: 132.9 UG/L (ppb)
Found at 68 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: 27 UG/L (ppb)
Found at 53 providers
One of the individual trihalomethane disinfection byproducts, formed when chlorine reacts with organic matter.
Bromoform
Detected: 76.2 UG/L (ppb)
Found at 65 providers
Bromodichloromethane
Detected: 18.3 UG/L (ppb)
Found at 63 providers
Dibromochloromethane
Detected: 41.8 UG/L (ppb)
Found at 68 providers
Inorganics
Common dissolved minerals and salts, e.g. nitrate, fluoride, chloride
Nitrate
Detected: 45 MG/L (ppm)
Found at 82 providers
Commonly from agricultural fertilizer runoff or septic systems. Above the legal limit, it's an immediate concern especially for infants.
Chloride
Detected: 310 MG/L (ppm)
Found at 32 providers
Sulfate
Detected: 430 MG/L (ppm)
Found at 31 providers
Fluoride
Detected: 3.2 MG/L (ppm)
Found at 42 providers
Often added deliberately for dental health; can also occur naturally.
Nitrate-Nitrite
Detected: 5.9 MG/L (ppm)
Found at 5 providers
Boron, Total
Detected: 4400 UG/L (ppb)
Found at 8 providers
Nitrite
Detected: 0.3 MG/L (ppm)
3/24/2025
Minerals
Everyday minerals that mainly affect taste and water hardness
Calcium
Detected: 170 MG/L (ppm)
Found at 34 providers
Magnesium
Detected: 1300 MG/L (ppm)
Found at 30 providers
Potassium
Detected: 9.3 MG/L (ppm)
Found at 19 providers
Sodium
Detected: 10000 MG/L (ppm)
Found at 34 providers
Properties
General water characteristics like pH, hardness, and cloudiness (turbidity)
pH
Detected: 9.1 PH
Found at 33 providers
A measure of how acidic or basic the water is (7 is neutral). Affects taste and plumbing, not a direct health measure.
Hardness, Total (ASCACO3)
Detected: 726 MG/L (ppm)
Found at 35 providers
Gross Alpha Particle Activity
Detected: 329 PCI/L
Found at 34 providers
Langelier Index (pH(s))
Detected: 1.46 LANG
Found at 9 providers
pH, Field
Detected: 8.11 PH
10/27/2025
Orthophosphate
Detected: 0.635 MG/L (ppm)
6/10/2025
PFAS & Emerging Contaminants
Human-made "forever chemicals" and other substances not yet fully regulated
Lithium
Detected: 51.6 ยตg/L (ppb)
Found at 25 providers
Occurs naturally in some groundwater. Not currently federally regulated in drinking water.
PFBS
Detected: 0.0075 ยตg/L (ppb)
Found at 5 providers
PFHXS
Detected: 0.1937 ยตg/L (ppb)
Found at 4 providers
PFOS
Detected: 0.0642 ยตg/L (ppb)
Found at 3 providers
One of two PFAS with an enforceable federal limit (4 ppt) since 2024.
PFBA
Detected: 0.01 ยตg/L (ppb)
Found at 4 providers
PFHXA
Detected: 0.0591 ยตg/L (ppb)
Found at 4 providers
PFOA
Detected: 0.1745 ยตg/L (ppb)
Found at 3 providers
One of two PFAS with an enforceable federal limit (4 ppt) since 2024.
PFPEA
Detected: 0.0358 ยตg/L (ppb)
Found at 4 providers
PFHPA
Detected: 0.048 ยตg/L (ppb)
Found at 2 providers
PFNA
Detected: 0.0084 ยตg/L (ppb)
11/19/2024
VOCs (Volatile Organic Compounds)
Industrial solvents and fuel-related chemicals that evaporate easily
Bromide
Detected: 0.69 MG/L (ppm)
Found at 8 providers
Trichloroethylene
Detected: 1.5 UG/L (ppb)
10/21/2025
Calculated Parameters
Values worked out mathematically from other test results, not measured directly
Alkalinity, Bicarbonate
Detected: 350 MG/L (ppm)
Found at 34 providers
Alkalinity, Carbonate
Detected: 34 MG/L (ppm)
Found at 6 providers
Other
Additional substances tested that don't fit neatly into the categories above
Dichloroaceticacid
Detected: 33.3 UG/L (ppb)
Found at 44 providers
Trichloroaceticacid
Detected: 8.2 UG/L (ppb)
Found at 35 providers
Dibromoaceticacid
Detected: 22.1 UG/L (ppb)
Found at 61 providers
Aggressive Index
Detected: 13 AGGR
Found at 25 providers
Alkalinity, Total
Detected: 290 MG/L (ppm)
Found at 36 providers
Turbidity
Detected: 21 NTU
Found at 23 providers
A measure of water cloudiness from suspended particles.
Radium-228
Detected: 1.39 PCI/L
Found at 13 providers
Combined Radium (-226 & -228)
Detected: 3.55 PCI/L
Found at 9 providers
A naturally occurring radioactive element found in some groundwater.
Color
Detected: 30 UNITS
Found at 11 providers
TDS
Detected: 1200 MG/L (ppm)
Found at 34 providers
Perchlorate
Detected: 4.9 UG/L (ppb)
Found at 6 providers
Can occur naturally or from industrial/military sources; may interfere with thyroid function at elevated levels.
Conductivity (at 25ยฐC)
Detected: 2200 UMHO/CM
Found at 32 providers
Langelier Index (Source Temp.)
Detected: 0.85 LANG
Found at 9 providers
Perfluorohexanesulfonicacid (PFHxS)
Detected: 52 NG/L (ppt)
Found at 9 providers
Perfluoroctanoicacid (PFOA)
Detected: 49 NG/L (ppt)
Found at 9 providers
One of two PFAS with an enforceable federal limit (4 ppt) since 2024.
Perfluorohexanoicacid (PFHXA)
Detected: 28 NG/L (ppt)
Found at 10 providers
Perfluorobutanesulfonicacid (PFBS)
Detected: 49 NG/L (ppt)
Found at 10 providers
Odor
Detected: 120 TON
Found at 10 providers
Monobromoaceticacid
Detected: 3.3 UG/L (ppb)
Found at 15 providers
Chlorite
Detected: 0.39 MG/L (ppm)
Found at 3 providers
Chlorate
Detected: 440 UG/L (ppb)
Found at 5 providers
Silica
Detected: 58.6 MG/L (ppm)
Found at 8 providers
Foamingagents (SURFACTANTS)
Detected: 0.2 MG/L (ppm)
Found at 6 providers
Perfluoroctanesulfonicacid (PFOS)
Detected: 140 NG/L (ppt)
Found at 7 providers
One of two PFAS with an enforceable federal limit (4 ppt) since 2024.
Perfluorobutanoicacid (PFBA)
Detected: 12 NG/L (ppt)
Found at 7 providers
Carbon, Total
Detected: 3.8 MG/L (ppm)
Found at 4 providers
Radium-226
Detected: 2.09 PCI/L
Found at 6 providers
Gross Beta Particle Activity
Detected: 109 PCI/L
Found at 5 providers
Perfluoropentanoicacid (PFPEA)
Detected: 22 NG/L (ppt)
Found at 9 providers
Perfluoropentanesulfonicacid (PFPES)
Detected: 7.9 NG/L (ppt)
Found at 5 providers
Perfluoroheptanoicacid (PFHPA)
Detected: 11 NG/L (ppt)
Found at 5 providers
Perfluorononanoicacid (PFNA)
Detected: 20 NG/L (ppt)
Found at 4 providers
Cyanide
Detected: 27 UG/L (ppb)
3/31/2025
Perfluoroundecanoicacid (PFUNA)
Detected: 5 NG/L (ppt)
6/26/2025
Perfluorooctanesulfonicacid6:2fts
Detected: 45 NG/L (ppt)
6/26/2025
Perfluorodecanesulfonicacid8:2fts
Detected: 9 NG/L (ppt)
6/26/2025
Perfluoroheptanesulfonicacid (PFHPS)
Detected: 5.4 NG/L (ppt)
Found at 2 providers
Monochloroaceticacid
Detected: 5 UG/L (ppb)
Found at 2 providers
Temperature (CENTIGRADE)
Detected: 25 C
6/18/2025
Adsorbableorganicfluorine
Detected: 1200 NG/L (ppt)
Found at 2 providers
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
Totalhaloaceticacids (HAA5)YesYesYes
BromideYesYesYes
LeadPartialYesPartial
ArsenicPartialYesPartial
Chromium-6 (Hexavalent)PartialYesPartial
CopperPartialYesPartial
Combined UraniumPartialYesPartial
PFOAPartialYes*Partial
PFOSPartialYes*Partial
NitratePartialYesPartial
Combined RadiumPartialYesPartial
DichloroaceticacidPartialYesPartial
TrichloroaceticacidPartialYesPartial
DibromoaceticacidPartialYesPartial
IronPartialYesPartial
ManganesePartialYesPartial
Aggressive IndexPartialYesPartial
Alkalinity, TotalPartialYesPartial
Combined Radium (-226 & -228)PartialYesPartial
ColorPartialYesPartial
Chromium, HexPartialYesPartial
Copper, FreePartialYesPartial
Combined UraniumPartialYesPartial
TDSPartialYesPartial
ChloridePartialYesPartial
SulfatePartialYesPartial
PerchloratePartialYesPartial
ChromiumPartialYesPartial
BariumPartialYesPartial
SeleniumPartialYesPartial
AluminumPartialYesPartial
ZincPartialYesPartial
Conductivity (at 25ยฐC)PartialYesPartial
FluoridePartialYesPartial
Langelier Index (Source Temp.)PartialYesPartial
Nitrate-NitritePartialYesPartial
Perfluorohexanesulfonicacid (PFHxS)PartialYesPartial
Perfluoroctanoicacid (PFOA)PartialYesPartial
Perfluorohexanoicacid (PFHXA)PartialYesPartial
Perfluorobutanesulfonicacid (PFBS)PartialYesPartial
OdorPartialYesPartial
Vanadium, TotalPartialYesPartial
LithiumPartialYes*Partial
MonobromoaceticacidPartialYesPartial
ChloritePartialYesPartial
ChloratePartialYesPartial
SilicaPartialYesPartial
PFBSPartialYes*Partial
PFHXSPartialYes*Partial
Foamingagents (SURFACTANTS)PartialYesPartial
Boron, TotalPartialYesPartial
Perfluoroctanesulfonicacid (PFOS)PartialYesPartial
Perfluorobutanoicacid (PFBA)PartialYesPartial
Carbon, TotalPartialYesPartial
PFBAPartialYes*Partial
PFHXAPartialYes*Partial
PFPEAPartialYes*Partial
Radium-226PartialYesPartial
Gross Beta Particle ActivityPartialYesPartial
NickelPartialYesPartial
PFHPAPartialYes*Partial
Molybdenum, TotalPartialYesPartial
Perfluoropentanoicacid (PFPEA)PartialYesPartial
Perfluoropentanesulfonicacid (PFPES)PartialYesPartial
Perfluoroheptanoicacid (PFHPA)PartialYesPartial
Perfluorononanoicacid (PFNA)PartialYesPartial
Iron, DissolvedPartialYesPartial
38-Strontium-90PartialYesPartial
CyanidePartialYesPartial
Perfluoroundecanoicacid (PFUNA)PartialYesPartial
Perfluorooctanesulfonicacid6:2ftsPartialYesPartial
Perfluorodecanesulfonicacid8:2ftsPartialYesPartial
Perfluoroheptanesulfonicacid (PFHPS)PartialYesPartial
MonochloroaceticacidPartialYesPartial
Temperature (CENTIGRADE)PartialYesPartial
AdsorbableorganicfluorinePartialYesPartial
NitritePartialYesPartial
SilverPartialYesPartial
PFNAPartialYes*Partial
Coliform Bacteria (indicator)NoYesNo
CalciumNoPartialNo
Alkalinity, BicarbonateNoNoNo
pHNoNoNo
MagnesiumNoPartialNo
PotassiumNoPartialNo
SodiumNoPartialNo
Hardness, Total (ASCACO3)NoNoNo
Gross Alpha Particle ActivityNoNoNo
Langelier Index (pH(s))NoNoNo
pH, FieldNoNoNo
Alkalinity, CarbonateNoNoNo
OrthophosphateNoNoNo

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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?