Serving roughly 110,088 people in Santa Clara County, California.
Data current as of July 2026
🔍Straight from EPA
🧪Real Lab Results
📅Updated Quarterly
🏠Local Expertise
Results for GREAT OAKS WC INC
1 water provider directly on file, serving roughly 110,088 people in Santa Clara County, California.
Quick answer: GREAT OAKS WC INC has no violations on file. One reading is worth knowing about: PFHXS was measured at 0.008µg/L, among the highest of the 320 providers on file in this area. It's the most notable figure in this system's record among its 320 local peers.
Lead Summary
Lithium
PFHXS
PFOS
PFHXA
PFPEA
Totalhaloaceticacids (HAA5)
TTHM
Bromoform
Bromodichloromethane
Dibromochloromethane
Dibromoaceticacid
Dichloroaceticacid
Trichloroaceticacid
Aggressive Index
Magnesium
Potassium
Sodium
Calcium
Alkalinity, Total
Alkalinity, Bicarbonate
Hardness, Total (ASCACO3)
TDS
Chloride
Sulfate
Fluoride
Nitrate
Utility GREAT OAKS WC INCPopulation served 110,088Owner Private
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
Disinfection Byproducts
Formed when chlorine used to disinfect water reacts with organic matter
Totalhaloaceticacids (HAA5)
Detected: 2.9 UG/L (ppb)
9/24/2025
TTHM
Detected: 23.52 UG/L (ppb)
9/24/2025
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.
Bromoform
Detected: 15.63 UG/L (ppb)
9/24/2025
Bromodichloromethane
Detected: 1.38 UG/L (ppb)
9/24/2025
Dibromochloromethane
Detected: 6.51 UG/L (ppb)
9/24/2025
Inorganics
Common dissolved minerals and salts, e.g. nitrate, fluoride, chloride
Chloride
Detected: 36 MG/L (ppm)
8/14/2025
Sulfate
Detected: 40 MG/L (ppm)
8/14/2025
Fluoride
Detected: 0.12 MG/L (ppm)
8/14/2025
Often added deliberately for dental health; can also occur naturally.
Nitrate
Detected: 1.6 MG/L (ppm)
8/13/2025
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: 41 MG/L (ppm)
8/14/2025
Potassium
Detected: 1.2 MG/L (ppm)
8/14/2025
Sodium
Detected: 27 MG/L (ppm)
8/14/2025
Calcium
Detected: 44 MG/L (ppm)
8/14/2025
Properties
General water characteristics like pH, hardness, and cloudiness (turbidity)
Hardness, Total (ASCACO3)
Detected: 277 MG/L (ppm)
8/14/2025
PFAS & Emerging Contaminants
Human-made "forever chemicals" and other substances not yet fully regulated
Lithium
Detected: 15.4 µg/L (ppb)
12/17/2025
Occurs naturally in some groundwater. Not currently federally regulated in drinking water.
PFHXS
Detected: 0.008 µg/L (ppb)
12/17/2025
PFOS
Detected: 0.0046 µg/L (ppb)
12/17/2025
One of two PFAS with an enforceable federal limit (4 ppt) since 2024.
PFHXA
Detected: 0.0045 µg/L (ppb)
12/17/2025
PFPEA
Detected: 0.0047 µg/L (ppb)
12/17/2025
Calculated Parameters
Values worked out mathematically from other test results, not measured directly
Alkalinity, Bicarbonate
Detected: 220 MG/L (ppm)
8/14/2025
Other
Additional substances tested that don't fit neatly into the categories above
Dibromoaceticacid
Detected: 2.9 UG/L (ppb)
9/24/2025
Dichloroaceticacid
Detected: 7.7 UG/L (ppb)
8/21/2025
Trichloroaceticacid
Detected: 3.2 UG/L (ppb)
8/21/2025
Aggressive Index
Detected: 12.15 AGGR
8/14/2025
Alkalinity, Total
Detected: 220 MG/L (ppm)
8/14/2025
TDS
Detected: 280 MG/L (ppm)
8/14/2025
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.