Serving roughly 3,329 people in Tehama County, California.
Data current as of July 2026
🔍Straight from EPA
🧪Real Lab Results
📅Updated Quarterly
🏠Local Expertise
Results for RIO ALTO WATER DISTRICT
1 water provider directly on file, serving roughly 3,329 people in Tehama County, California.
Quick answer: RIO ALTO WATER DISTRICT has no violations on file. One reading is worth knowing about: Fluoride was measured at 0.2MG/L, among the highest of the 215 providers on file in this area. It's the most notable figure in this system's record among its 215 local peers.
Lead Summary
Copper, Free
Aggressive Index
Langelier Index (pH(s))
Magnesium
Potassium
Sodium
Hardness, Total (ASCACO3)
Calcium
Alkalinity, Total
Alkalinity, Bicarbonate
TDS
Chloride
Sulfate
Fluoride
Nitrate
Nitrate-Nitrite
pH, Field
Chromium, Hex
Arsenic
Conductivity (at 25°C)
Utility RIO ALTO WATER DISTRICTPopulation served 3,329Owner 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)
12/31/2025
Copper, Free
Detected: 51 UG/L (ppb)
9/10/2025
Chromium, Hex
Detected: 4.4 UG/L (ppb)
3/5/2025
Arsenic
Detected: 3 UG/L (ppb)
9/17/2025
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: 3 MG/L (ppm)
9/17/2025
Sulfate
Detected: 1.9 MG/L (ppm)
9/17/2025
Fluoride
Detected: 0.2 MG/L (ppm)
9/17/2025
Often added deliberately for dental health; can also occur naturally.
Nitrate
Detected: 0.7 MG/L (ppm)
10/29/2025
Commonly from agricultural fertilizer runoff or septic systems. Above the legal limit, it's an immediate concern especially for infants.
Nitrate-Nitrite
Detected: 0.7 MG/L (ppm)
9/17/2025
Minerals
Everyday minerals that mainly affect taste and water hardness
Magnesium
Detected: 8 MG/L (ppm)
9/17/2025
Potassium
Detected: 3 MG/L (ppm)
9/17/2025
Sodium
Detected: 15 MG/L (ppm)
9/17/2025
Calcium
Detected: 12 MG/L (ppm)
9/17/2025
Properties
General water characteristics like pH, hardness, and cloudiness (turbidity)
Langelier Index (pH(s))
Detected: -0.3 LANG
9/17/2025
Hardness, Total (ASCACO3)
Detected: 62.9 MG/L (ppm)
9/17/2025
pH, Field
Detected: 8.14 PH
9/17/2025
Calculated Parameters
Values worked out mathematically from other test results, not measured directly
Alkalinity, Bicarbonate
Detected: 110 MG/L (ppm)
9/17/2025
Other
Additional substances tested that don't fit neatly into the categories above
Aggressive Index
Detected: 11.5 AGGR
9/17/2025
Alkalinity, Total
Detected: 90 MG/L (ppm)
9/17/2025
TDS
Detected: 190 MG/L (ppm)
9/17/2025
Conductivity (at 25°C)
Detected: 191 UMHO/CM
9/17/2025
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.