Serving roughly 7,038 people in San Bernardino County, California.
Data current as of July 2026
🔍Straight from EPA
🧪Real Lab Results
📅Updated Quarterly
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Results for LAKE ARROWHEAD CSD
1 water provider directly on file, serving roughly 7,038 people in San Bernardino County, California.
Quick answer: LAKE ARROWHEAD CSD has no violations on file. One reading is worth knowing about: TTHM was measured at 111.1UG/L, among the highest of the 669 providers on file in this area. It's the most notable figure in this system's record among its 669 local peers.
Lead Summary
PFPEA
PFOA
PFHXA
PFOS
PFHPA
Pfda
PFHXS
PFNA
Totalhaloaceticacids (HAA5)
TTHM
Chloroform
Bromoform
Bromodichloromethane
Dibromochloromethane
Dichloroaceticacid
Trichloroaceticacid
Dibromoaceticacid
Magnesium
Potassium
Sodium
Hardness, Total (ASCACO3)
Calcium
Alkalinity, Total
Alkalinity, Bicarbonate
Carbon, Total
Foamingagents (SURFACTANTS)
TDS
Chloride
Sulfate
pH
Odor
Conductivity (at 25°C)
Gross Alpha Particle Activity
Fluoride
Nitrate
Perfluorobutanesulfonicacid (PFBS)
Perfluoroctanesulfonicacid (PFOS)
Perfluorohexanesulfonicacid (PFHxS)
Perfluoroctanoicacid (PFOA)
Perfluorohexanoicacid (PFHXA)
Perfluorobutanoicacid (PFBA)
Perfluoropentanoicacid (PFPEA)
Radium-226
Radium-228
Combined Uranium
Combined Radium (-226 & -228)
Utility LAKE ARROWHEAD CSDPopulation served 7,038Owner 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)
12/31/2023
Combined Uranium
Detected: 100 PCI/L
10/1/2025
A naturally occurring radioactive metal. Long-term exposure above the legal limit is associated with kidney effects and increased cancer risk.
Disinfection Byproducts
Formed when chlorine used to disinfect water reacts with organic matter
Totalhaloaceticacids (HAA5)
Detected: 11.1 UG/L (ppb)
8/20/2025
TTHM
Detected: 111.1 UG/L (ppb)
8/20/2025
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.
Chloroform
Detected: 26.6 UG/L (ppb)
8/20/2025
One of the individual trihalomethane disinfection byproducts, formed when chlorine reacts with organic matter.
Bromoform
Detected: 22.7 UG/L (ppb)
8/20/2025
Bromodichloromethane
Detected: 28.4 UG/L (ppb)
8/20/2025
Dibromochloromethane
Detected: 33.4 UG/L (ppb)
8/20/2025
Inorganics
Common dissolved minerals and salts, e.g. nitrate, fluoride, chloride
Chloride
Detected: 17 MG/L (ppm)
7/9/2025
Sulfate
Detected: 5.6 MG/L (ppm)
7/9/2025
Fluoride
Detected: 0.19 MG/L (ppm)
7/9/2025
Often added deliberately for dental health; can also occur naturally.
Nitrate
Detected: 0.45 MG/L (ppm)
6/18/2025
Commonly from agricultural fertilizer runoff or septic systems. Above the legal limit, it's an immediate concern especially for infants.
Minerals
Everyday minerals that mainly affect taste and water hardness
Magnesium
Detected: 3.5 MG/L (ppm)
7/9/2025
Potassium
Detected: 1.9 MG/L (ppm)
7/9/2025
Sodium
Detected: 14 MG/L (ppm)
7/9/2025
Calcium
Detected: 19 MG/L (ppm)
7/9/2025
Properties
General water characteristics like pH, hardness, and cloudiness (turbidity)
Hardness, Total (ASCACO3)
Detected: 62 MG/L (ppm)
7/9/2025
pH
Detected: 6.9 PH
10/1/2025
A measure of how acidic or basic the water is (7 is neutral). Affects taste and plumbing, not a direct health measure.
Gross Alpha Particle Activity
Detected: 3.4 PCI/L
10/7/2025
PFAS & Emerging Contaminants
Human-made "forever chemicals" and other substances not yet fully regulated
PFPEA
Detected: 0.0037 µg/L (ppb)
7/10/2024
PFOA
Detected: 0.011 µg/L (ppb)
7/10/2024
One of two PFAS with an enforceable federal limit (4 ppt) since 2024.
PFHXA
Detected: 0.0048 µg/L (ppb)
7/10/2024
PFOS
Detected: 0.005 µg/L (ppb)
7/10/2024
One of two PFAS with an enforceable federal limit (4 ppt) since 2024.
PFHPA
Detected: 0.0044 µg/L (ppb)
7/10/2024
Pfda
Detected: 0.0034 µg/L (ppb)
1/31/2024
PFHXS
Detected: 0.0033 µg/L (ppb)
8/7/2023
PFNA
Detected: 0.0046 µg/L (ppb)
8/7/2023
Calculated Parameters
Values worked out mathematically from other test results, not measured directly
Alkalinity, Bicarbonate
Detected: 76 MG/L (ppm)
7/9/2025
Other
Additional substances tested that don't fit neatly into the categories above
Dichloroaceticacid
Detected: 4.1 UG/L (ppb)
8/20/2025
Trichloroaceticacid
Detected: 1.3 UG/L (ppb)
8/20/2025
Dibromoaceticacid
Detected: 5.7 UG/L (ppb)
8/20/2025
Alkalinity, Total
Detected: 62 MG/L (ppm)
7/9/2025
Carbon, Total
Detected: 2.3 MG/L (ppm)
10/1/2025
Foamingagents (SURFACTANTS)
Detected: 0.39 MG/L (ppm)
7/9/2025
TDS
Detected: 81 MG/L (ppm)
7/9/2025
Odor
Detected: 1 TON
7/9/2025
Conductivity (at 25°C)
Detected: 200 UMHO/CM
7/9/2025
Perfluorobutanesulfonicacid (PFBS)
Detected: 4.3 NG/L (ppt)
8/20/2025
Perfluoroctanesulfonicacid (PFOS)
Detected: 4.3 NG/L (ppt)
8/20/2025
One of two PFAS with an enforceable federal limit (4 ppt) since 2024.
Perfluorohexanesulfonicacid (PFHxS)
Detected: 2 NG/L (ppt)
8/20/2025
Perfluoroctanoicacid (PFOA)
Detected: 4.6 NG/L (ppt)
8/20/2025
One of two PFAS with an enforceable federal limit (4 ppt) since 2024.
Perfluorohexanoicacid (PFHXA)
Detected: 3 NG/L (ppt)
8/20/2025
Perfluorobutanoicacid (PFBA)
Detected: 2.3 NG/L (ppt)
3/4/2025
Perfluoropentanoicacid (PFPEA)
Detected: 2.8 NG/L (ppt)
8/20/2025
Radium-226
Detected: 2.74 PCI/L
9/10/2025
Radium-228
Detected: 0.737 PCI/L
9/10/2025
Combined Radium (-226 & -228)
Detected: 3.48 PCI/L
9/10/2025
A naturally occurring radioactive element found in some groundwater.
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.