Serving roughly 8,234 people in Mono County, California.
Data current as of July 2026
🔍Straight from EPA
🧪Real Lab Results
📅Updated Quarterly
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Results for MAMMOTH CWD
1 water provider directly on file, serving roughly 8,234 people in Mono County, California.
Quick answer: MAMMOTH CWD has no violations on file and no single reading stands out against its peers (127 other providers in this area). It serves roughly 8,234 people, and the full breakdown below reflects everything EPA and California have on record for it.
Lead Summary
Copper Summary
Lithium
Totalhaloaceticacids (HAA5)
TTHM
Chloroform
Bromodichloromethane
Dichloroaceticacid
Trichloroaceticacid
Iron
Arsenic
Nitrate
Manganese
Sodium
Calcium
Alkalinity, Total
Alkalinity, Bicarbonate
Hardness, Total (ASCACO3)
TDS
Sulfate
Turbidity
pH
Conductivity (at 25°C)
Utility MAMMOTH CWDPopulation served 8,234Owner 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
Copper Summary
Detected: 1.4 mg/L (ppm)
06/30/2015
Iron
Detected: 95 UG/L (ppb)
9/10/2025
Mostly an aesthetic issue (metallic taste, staining) rather than a health concern at typical levels.
Arsenic
Detected: 5.2 UG/L (ppb)
9/10/2025
Occurs naturally in some groundwater. Long-term exposure above the legal limit (10 ppb) has been linked to increased cancer risk and cardiovascular disease.
Manganese
Detected: 540 UG/L (ppb)
9/10/2025
Mainly a taste/staining concern at typical levels; long-term neurological research at high chronic exposure is ongoing.
Disinfection Byproducts
Formed when chlorine used to disinfect water reacts with organic matter
Totalhaloaceticacids (HAA5)
Detected: 9.3 UG/L (ppb)
7/9/2025
TTHM
Detected: 16 UG/L (ppb)
7/9/2025
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: 15 UG/L (ppb)
7/9/2025
One of the individual trihalomethane disinfection byproducts, formed when chlorine reacts with organic matter.
Bromodichloromethane
Detected: 0.74 UG/L (ppb)
7/9/2025
Inorganics
Common dissolved minerals and salts, e.g. nitrate, fluoride, chloride
Nitrate
Detected: 0.21 MG/L (ppm)
9/10/2025
Commonly from agricultural fertilizer runoff or septic systems. Above the legal limit, it's an immediate concern especially for infants.
Sulfate
Detected: 2.1 MG/L (ppm)
7/15/2025
Minerals
Everyday minerals that mainly affect taste and water hardness
Sodium
Detected: 1.2 MG/L (ppm)
7/15/2025
Calcium
Detected: 6 MG/L (ppm)
7/15/2025
Properties
General water characteristics like pH, hardness, and cloudiness (turbidity)
Hardness, Total (ASCACO3)
Detected: 16 MG/L (ppm)
7/15/2025
pH
Detected: 6.8 PH
7/15/2025
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: 96.7 µg/L (ppb)
8/12/2025
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: 21 MG/L (ppm)
7/15/2025
Other
Additional substances tested that don't fit neatly into the categories above
Dichloroaceticacid
Detected: 4.4 UG/L (ppb)
7/9/2025
Trichloroaceticacid
Detected: 4.9 UG/L (ppb)
7/9/2025
Alkalinity, Total
Detected: 21 MG/L (ppm)
7/15/2025
TDS
Detected: 17 MG/L (ppm)
7/15/2025
Turbidity
Detected: 0.28 NTU
7/15/2025
A measure of water cloudiness from suspended particles.
Conductivity (at 25°C)
Detected: 41 UMHO/CM
7/15/2025
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.