TESORO VIEJO MASTER MWC, INC. Water Quality Report
Serving roughly 3,885 people in Madera County, California.
Data current as of July 2026
🔍Straight from EPA
🧪Real Lab Results
📅Updated Quarterly
🏠Local Expertise
Results for TESORO VIEJO MASTER MWC, INC.
1 water provider directly on file, serving roughly 3,885 people in Madera County, California.
Quick answer: TESORO VIEJO MASTER MWC, INC. has no violations on file. One reading is worth knowing about: Bromodichloromethane was measured at 3.7UG/L, among the highest of the 311 providers on file in this area. It's the most notable figure in this system's record among its 311 local peers.
Lead Summary
pH, Field
Totalhaloaceticacids (HAA5)
TTHM
Chloroform
Bromodichloromethane
Dichloroaceticacid
Trichloroaceticacid
Monochloroaceticacid
Aggressive Index
Langelier Index (pH(s))
Magnesium
Sodium
Calcium
Alkalinity, Total
Alkalinity, Bicarbonate
Hardness, Total (ASCACO3)
Carbon, Total
Foamingagents (SURFACTANTS)
TDS
Chloride
Sulfate
Turbidity
Radium-226
Combined Uranium
Strontium
Iron
Manganese
Barium
Aluminum
Copper, Free
Conductivity (at 25°C)
Color
Arsenic
Odor
Utility TESORO VIEJO MASTER MWC, INC.Population served 3,885Owner 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)
12/31/2024
Combined Uranium
Detected: 0.68 PCI/L
6/17/2025
A naturally occurring radioactive metal. Long-term exposure above the legal limit is associated with kidney effects and increased cancer risk.
Strontium
Detected: 44 UG/L (ppb)
6/17/2025
Iron
Detected: 80 UG/L (ppb)
9/16/2025
Mostly an aesthetic issue (metallic taste, staining) rather than a health concern at typical levels.
Manganese
Detected: 12 UG/L (ppb)
9/16/2025
Mainly a taste/staining concern at typical levels; long-term neurological research at high chronic exposure is ongoing.
Barium
Detected: 27 UG/L (ppb)
6/17/2025
Aluminum
Detected: 370 UG/L (ppb)
6/17/2025
Copper, Free
Detected: 6.4 UG/L (ppb)
5/5/2025
Arsenic
Detected: 2.1 UG/L (ppb)
2/10/2025
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: 39 UG/L (ppb)
10/6/2025
TTHM
Detected: 68 UG/L (ppb)
10/6/2025
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: 65 UG/L (ppb)
10/6/2025
One of the individual trihalomethane disinfection byproducts, formed when chlorine reacts with organic matter.
Bromodichloromethane
Detected: 3.7 UG/L (ppb)
10/6/2025
Inorganics
Common dissolved minerals and salts, e.g. nitrate, fluoride, chloride
Chloride
Detected: 2.8 MG/L (ppm)
6/3/2025
Sulfate
Detected: 1.4 MG/L (ppm)
6/3/2025
Minerals
Everyday minerals that mainly affect taste and water hardness
Magnesium
Detected: 0.84 MG/L (ppm)
6/3/2025
Sodium
Detected: 4.2 MG/L (ppm)
6/3/2025
Calcium
Detected: 15 MG/L (ppm)
10/6/2025
Properties
General water characteristics like pH, hardness, and cloudiness (turbidity)
pH, Field
Detected: 7.24 PH
10/21/2025
Langelier Index (pH(s))
Detected: -0.3 LANG
10/6/2025
Hardness, Total (ASCACO3)
Detected: 14 MG/L (ppm)
6/3/2025
Calculated Parameters
Values worked out mathematically from other test results, not measured directly
Alkalinity, Bicarbonate
Detected: 17 MG/L (ppm)
10/6/2025
Other
Additional substances tested that don't fit neatly into the categories above
Dichloroaceticacid
Detected: 17 UG/L (ppb)
10/6/2025
Trichloroaceticacid
Detected: 22 UG/L (ppb)
10/6/2025
Monochloroaceticacid
Detected: 2.2 UG/L (ppb)
4/7/2025
Aggressive Index
Detected: 9.45 AGGR
6/3/2025
Alkalinity, Total
Detected: 17 MG/L (ppm)
10/6/2025
Carbon, Total
Detected: 2.3 MG/L (ppm)
10/21/2025
Foamingagents (SURFACTANTS)
Detected: 0.054 MG/L (ppm)
6/3/2025
TDS
Detected: 66 MG/L (ppm)
10/6/2025
Turbidity
Detected: 1 NTU
6/3/2025
A measure of water cloudiness from suspended particles.
Radium-226
Detected: 0.47 PCI/L
3/10/2025
Conductivity (at 25°C)
Detected: 51 UMHO/CM
6/3/2025
Color
Detected: 5 UNITS
6/3/2025
Odor
Detected: 1.2 TON
6/2/2025
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.