CUPERTINO is served by 1 water provider on file with the EPA.
Data current as of July 2026
🔍Straight from EPA
🧪Real Lab Results
📅Updated Quarterly
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Results for CUPERTINO, CA
1 water provider on file serving this city.
Quick answer: CUPERTINO's water has no violations on file and no single reading stands out against its peers (1 other providers in this area). It serves roughly 16,336 people, and the full breakdown below reflects everything EPA and California have on record for it.
Lead Summary
Aggressive Index
Langelier Index (Source Temp.)
Magnesium
Potassium
Sodium
Calcium
Alkalinity, Total
Alkalinity, Bicarbonate
Hardness, Total (ASCACO3)
TDS
Chloride
Sulfate
Fluoride
Nitrate
Nitrate-Nitrite
Carbondioxide
Barium
Arsenic
Conductivity (at 25°C)
Contaminants found
Metals
Naturally occurring or corrosion-related elements, e.g. lead, arsenic, copper
Lead Summary
Detected: 0 mg/L (ppm)
12/31/2022
Barium
Detected: 120 UG/L (ppb)
2/20/2025
Arsenic
Detected: 2.2 UG/L (ppb)
2/20/2025
Occurs naturally in some groundwater. Long-term exposure above the legal limit (10 ppb) has been linked to increased cancer risk and cardiovascular disease.
Inorganics
Common dissolved minerals and salts, e.g. nitrate, fluoride, chloride
Chloride
Detected: 47 MG/L (ppm)
2/20/2025
Sulfate
Detected: 41 MG/L (ppm)
2/20/2025
Fluoride
Detected: 0.14 MG/L (ppm)
2/20/2025
Often added deliberately for dental health; can also occur naturally.
Nitrate
Detected: 4 MG/L (ppm)
2/20/2025
Commonly from agricultural fertilizer runoff or septic systems. Above the legal limit, it's an immediate concern especially for infants.
Nitrate-Nitrite
Detected: 4 MG/L (ppm)
2/20/2025
Minerals
Everyday minerals that mainly affect taste and water hardness
Magnesium
Detected: 27 MG/L (ppm)
2/20/2025
Potassium
Detected: 1.2 MG/L (ppm)
2/20/2025
Sodium
Detected: 27 MG/L (ppm)
2/20/2025
Calcium
Detected: 86 MG/L (ppm)
2/20/2025
Properties
General water characteristics like pH, hardness, and cloudiness (turbidity)
Hardness, Total (ASCACO3)
Detected: 324 MG/L (ppm)
2/20/2025
Calculated Parameters
Values worked out mathematically from other test results, not measured directly
Alkalinity, Bicarbonate
Detected: 240 MG/L (ppm)
2/20/2025
Other
Additional substances tested that don't fit neatly into the categories above
Aggressive Index
Detected: 11.8 AGGR
2/20/2025
Langelier Index (Source Temp.)
Detected: -0.32 LANG
2/20/2025
Alkalinity, Total
Detected: 240 MG/L (ppm)
2/20/2025
TDS
Detected: 390 MG/L (ppm)
2/20/2025
Carbondioxide
Detected: 40000 UG/L (ppb)
2/20/2025
Conductivity (at 25°C)
Detected: 670 UMHO/CM
2/20/2025
Filtration considerations: General system types, not a specific product recommendation.