Serving roughly 61,691 people in Marin County, California.
Data current as of July 2026
🔍Straight from EPA
🧪Real Lab Results
📅Updated Quarterly
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Results for NORTH MARIN WATER DISTRICT
1 water provider directly on file, serving roughly 61,691 people in Marin County, California.
Quick answer: NORTH MARIN WATER DISTRICT has no violations on file and no single reading stands out against its peers (103 other providers in this area). It serves roughly 61,691 people, and the full breakdown below reflects everything EPA and California have on record for it.
Lead Summary
Copper Summary
Totalhaloaceticacids (HAA5)
TTHM
Chloroform
Bromodichloromethane
Dibromochloromethane
Dichloroaceticacid
Trichloroaceticacid
Dibromoaceticacid
Bromoform
Magnesium
Sodium
Manganese
Chromium, Hex
Arsenic
Utility NORTH MARIN WATER DISTRICTPopulation served 61,691Owner 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: 1.95 mg/L (ppm)
12/31/1992
Manganese
Detected: 140 UG/L (ppb)
9/8/2025
Mainly a taste/staining concern at typical levels; long-term neurological research at high chronic exposure is ongoing.
Chromium, Hex
Detected: 0.275 UG/L (ppb)
3/28/2025
Arsenic
Detected: 3.3 UG/L (ppb)
9/8/2025
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
Totalhaloaceticacids (HAA5)
Detected: 5.71 UG/L (ppb)
8/13/2025
TTHM
Detected: 26.18 UG/L (ppb)
8/13/2025
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: 15.22 UG/L (ppb)
8/13/2025
One of the individual trihalomethane disinfection byproducts, formed when chlorine reacts with organic matter.
Bromodichloromethane
Detected: 8.14 UG/L (ppb)
8/13/2025
Dibromochloromethane
Detected: 2.82 UG/L (ppb)
8/13/2025
Bromoform
Detected: 1.08 UG/L (ppb)
8/13/2025
Minerals
Everyday minerals that mainly affect taste and water hardness
Magnesium
Detected: 12 MG/L (ppm)
9/8/2025
Sodium
Detected: 13 MG/L (ppm)
9/8/2025
Other
Additional substances tested that don't fit neatly into the categories above
Dichloroaceticacid
Detected: 3.41 UG/L (ppb)
8/13/2025
Trichloroaceticacid
Detected: 2.3 UG/L (ppb)
8/13/2025
Dibromoaceticacid
Detected: 1.39 UG/L (ppb)
8/13/2025
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.