Serving roughly 175,396 people in Sonoma County, California.
Data current as of July 2026
🔍Straight from EPA
🧪Real Lab Results
📅Updated Quarterly
🏠Local Expertise
Results for SANTA ROSA, CITY OF
1 water provider directly on file, serving roughly 175,396 people in Sonoma County, California.
Quick answer: SANTA ROSA, CITY OF has no violations on file. One reading is worth knowing about: Lithium was measured at 95µg/L, among the highest of the 756 providers on file in this area. It's the most notable figure in this system's record among its 756 local peers.
Lead Summary
Copper Summary
Lithium
Totalhaloaceticacids (HAA5)
TTHM
Chromium, Hex
Chloroform
Bromodichloromethane
Dibromochloromethane
Bromoform
Dichloroaceticacid
Trichloroaceticacid
Dibromoaceticacid
Manganese
Odor
Utility SANTA ROSA, CITY OFPopulation served 175,396Owner Local government
Naturally occurring or corrosion-related elements, e.g. lead, arsenic, copper
Lead Summary
Detected: 0.00132 mg/L (ppm)
12/31/2025
Copper Summary
Detected: 2.4 mg/L (ppm)
12/31/1992
Chromium, Hex
Detected: 0.344 UG/L (ppb)
1/14/2025
Manganese
Detected: 2.69 UG/L (ppb)
9/8/2025
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: 10 UG/L (ppb)
7/8/2025
TTHM
Detected: 19 UG/L (ppb)
10/20/2025
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: 8.4 UG/L (ppb)
10/20/2025
One of the individual trihalomethane disinfection byproducts, formed when chlorine reacts with organic matter.
Bromodichloromethane
Detected: 5.5 UG/L (ppb)
10/20/2025
Dibromochloromethane
Detected: 3.8 UG/L (ppb)
10/20/2025
Bromoform
Detected: 1.2 UG/L (ppb)
10/20/2025
PFAS & Emerging Contaminants
Human-made "forever chemicals" and other substances not yet fully regulated
Lithium
Detected: 95 µg/L (ppb)
11/5/2024
Occurs naturally in some groundwater. Not currently federally regulated in drinking water.
Other
Additional substances tested that don't fit neatly into the categories above
Dichloroaceticacid
Detected: 5.7 UG/L (ppb)
7/8/2025
Trichloroaceticacid
Detected: 1.8 UG/L (ppb)
7/8/2025
Dibromoaceticacid
Detected: 2.5 UG/L (ppb)
7/8/2025
Odor
Detected: 3.8 TON
1/14/2025
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.