MODESTO is served by 15 water providers on file with the EPA.
Data current as of July 2026
🔍Straight from EPA
🧪Real Lab Results
📅Updated Quarterly
🏠Local Expertise
Results for MODESTO, CA
15 water providers on file serving this city.
Quick answer: MODESTO's water has no violations on file. One reading is worth knowing about: Lead Summary was measured at 0.012mg/L, among the highest of the 15 providers on file in this area. It's the most notable figure in this system's record among its 15 local peers.
Lead Summary
Lithium
Aggressive Index
Magnesium
Potassium
Calcium
Alkalinity, Total
Alkalinity, Bicarbonate
Hardness, Total (ASCACO3)
TDS
Chloride
Sulfate
Nitrate
Perfluorobutanesulfonicacid (PFBS)
Perfluoropfmba
Perfluorohexanoicacid (PFHXA)
Perfluoropentanoicacid (PFPEA)
Perfluoropfeesa
Hfpo-Da
Perfluorohexanesulfonicacid4:2fts
Perfluoropfmpa
Perfluoropentanesulfonicacid (PFPES)
Perfluoroheptanoicacid (PFHPA)
Adona
Perfluorooctanesulfonicacid6:2fts
Perfluoroheptanesulfonicacid (PFHPS)
Nonafluoronfdha
Perfluorohexanesulfonicacid (PFHxS)
9cl-Pf3ons
Perfluoroctanesulfonicacid (PFOS)
Perfluoroctanoicacid (PFOA)
Perfluorononanoicacid (PFNA)
Perfluorodecanesulfonicacid8:2fts
pH
Iron
Chromium, Hex
Barium
Arsenic
Conductivity (at 25°C)
Totalhaloaceticacids (HAA5)
TTHM
Chloroform
Bromodichloromethane
Dibromochloromethane
Bromoform
Dichloroaceticacid
Trichloroaceticacid
Dibromoaceticacid
1, 2-Dibromo-3-Chloropropane
Turbidity
Manganese
PFOS
PFHXS
PFOA
PFHXA
PFPEA
PFHPA
PFBS
Sodium
Fluoride
Adsorbableorganicfluorine
Perfluorobutanoicacid (PFBA)
Combined Uranium
Color
Nitrite
Nitrate-Nitrite
Odor
Copper, Free
1, 2, 3-Trichloropropane
Perchlorate
Chromium
Selenium
Gross Alpha Particle Activity
Vanadium, Total
Cadmium
Violations on file
Fluoride
Older/archived health-based violation
Found at 1 of 15 providers
Often added deliberately for dental health; can also occur naturally.
Nitrate
Older/archived health-based violation
Found at 1 of 15 providers
Commonly from agricultural fertilizer runoff or septic systems. Above the legal limit, it's an immediate concern especially for infants.
Selenium
Older/archived health-based violation
Found at 1 of 15 providers
Arsenic
Older/archived health-based violation
Found at 1 of 15 providers
Occurs naturally in some groundwater. Long-term exposure above the legal limit (10 ppb) has been linked to increased cancer risk and cardiovascular disease.
Contaminants found
Metals
Naturally occurring or corrosion-related elements, e.g. lead, arsenic, copper
Lead Summary
Detected: 0.012 mg/L (ppm)
Found at 13 providers
Iron
Detected: 230 UG/L (ppb)
Found at 2 providers
Mostly an aesthetic issue (metallic taste, staining) rather than a health concern at typical levels.
Chromium, Hex
Detected: 8.79 UG/L (ppb)
Found at 9 providers
Barium
Detected: 160 UG/L (ppb)
Found at 4 providers
Arsenic
Detected: 8.2 UG/L (ppb)
Found at 6 providers
Occurs naturally in some groundwater. Long-term exposure above the legal limit (10 ppb) has been linked to increased cancer risk and cardiovascular disease.
Manganese
Detected: 75.3 UG/L (ppb)
Found at 2 providers
Mainly a taste/staining concern at typical levels; long-term neurological research at high chronic exposure is ongoing.
Combined Uranium
Detected: 14 PCI/L
Found at 3 providers
A naturally occurring radioactive metal. Long-term exposure above the legal limit is associated with kidney effects and increased cancer risk.
Copper, Free
Detected: 110 UG/L (ppb)
8/26/2025
Chromium
Detected: 21 UG/L (ppb)
5/6/2025
Occurs in two forms — trivalent (an essential nutrient in trace amounts) and hexavalent (linked to increased cancer risk).
Selenium
Detected: 5.2 UG/L (ppb)
5/6/2025
Vanadium, Total
Detected: 22 UG/L (ppb)
2/3/2025
Cadmium
Detected: 1.4 UG/L (ppb)
2/3/2025
Disinfection Byproducts
Formed when chlorine used to disinfect water reacts with organic matter
Totalhaloaceticacids (HAA5)
Detected: 10.3 UG/L (ppb)
Found at 3 providers
TTHM
Detected: 42 UG/L (ppb)
Found at 4 providers
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: 34.55 UG/L (ppb)
Found at 2 providers
One of the individual trihalomethane disinfection byproducts, formed when chlorine reacts with organic matter.
Bromodichloromethane
Detected: 5.75 UG/L (ppb)
Found at 2 providers
Dibromochloromethane
Detected: 1.7 UG/L (ppb)
Found at 4 providers
Bromoform
Detected: 4.93 UG/L (ppb)
Found at 2 providers
Inorganics
Common dissolved minerals and salts, e.g. nitrate, fluoride, chloride
Chloride
Detected: 27 MG/L (ppm)
Found at 4 providers
Sulfate
Detected: 23 MG/L (ppm)
Found at 4 providers
Nitrate
Detected: 10.3 MG/L (ppm)
Found at 12 providers
Commonly from agricultural fertilizer runoff or septic systems. Above the legal limit, it's an immediate concern especially for infants.
Fluoride
Detected: 0.12 MG/L (ppm)
5/21/2025
Often added deliberately for dental health; can also occur naturally.
Nitrite
Detected: 0.41 MG/L (ppm)
4/24/2025
Nitrate-Nitrite
Detected: 10 MG/L (ppm)
Found at 2 providers
Minerals
Everyday minerals that mainly affect taste and water hardness
Magnesium
Detected: 150 MG/L (ppm)
Found at 6 providers
Potassium
Detected: 6.1 MG/L (ppm)
Found at 4 providers
Calcium
Detected: 76 MG/L (ppm)
Found at 6 providers
Sodium
Detected: 160 MG/L (ppm)
Found at 5 providers
Properties
General water characteristics like pH, hardness, and cloudiness (turbidity)
Hardness, Total (ASCACO3)
Detected: 735 MG/L (ppm)
Found at 6 providers
pH
Detected: 7.93 PH
Found at 4 providers
A measure of how acidic or basic the water is (7 is neutral). Affects taste and plumbing, not a direct health measure.
Gross Alpha Particle Activity
Detected: 16.8 PCI/L
8/21/2025
PFAS & Emerging Contaminants
Human-made "forever chemicals" and other substances not yet fully regulated
Lithium
Detected: 12 µg/L (ppb)
Found at 2 providers
Occurs naturally in some groundwater. Not currently federally regulated in drinking water.
PFOS
Detected: 0.0046 µg/L (ppb)
9/12/2024
One of two PFAS with an enforceable federal limit (4 ppt) since 2024.
PFHXS
Detected: 0.0069 µg/L (ppb)
9/12/2024
PFOA
Detected: 0.0041 µg/L (ppb)
9/12/2024
One of two PFAS with an enforceable federal limit (4 ppt) since 2024.
PFHXA
Detected: 0.0039 µg/L (ppb)
9/12/2024
PFPEA
Detected: 0.0046 µg/L (ppb)
9/12/2024
PFHPA
Detected: 0.0036 µg/L (ppb)
8/28/2024
PFBS
Detected: 0.0034 µg/L (ppb)
9/12/2024
VOCs (Volatile Organic Compounds)
Industrial solvents and fuel-related chemicals that evaporate easily
1, 2, 3-Trichloropropane
Detected: 0.015 UG/L (ppb)
Found at 2 providers
Calculated Parameters
Values worked out mathematically from other test results, not measured directly
Alkalinity, Bicarbonate
Detected: 200 MG/L (ppm)
Found at 6 providers
Other
Additional substances tested that don't fit neatly into the categories above
Aggressive Index
Detected: 12.21 AGGR
Found at 4 providers
Alkalinity, Total
Detected: 200 MG/L (ppm)
Found at 6 providers
TDS
Detected: 290 MG/L (ppm)
Found at 4 providers
Perfluorobutanesulfonicacid (PFBS)
Detected: 5.2 NG/L (ppt)
Found at 2 providers
Perfluoropfmba
Detected: 4.6 NG/L (ppt)
6/11/2025
Perfluorohexanoicacid (PFHXA)
Detected: 5 NG/L (ppt)
Found at 2 providers
Perfluoropentanoicacid (PFPEA)
Detected: 5.2 NG/L (ppt)
Found at 2 providers
Perfluoropfeesa
Detected: 5.1 NG/L (ppt)
6/11/2025
Hfpo-Da
Detected: 5.1 NG/L (ppt)
6/11/2025
Perfluorohexanesulfonicacid4:2fts
Detected: 5.1 NG/L (ppt)
6/11/2025
Perfluoropfmpa
Detected: 4.4 NG/L (ppt)
6/11/2025
Perfluoropentanesulfonicacid (PFPES)
Detected: 5.2 NG/L (ppt)
Found at 2 providers
Perfluoroheptanoicacid (PFHPA)
Detected: 4.5 NG/L (ppt)
Found at 2 providers
Adona
Detected: 4.1 NG/L (ppt)
6/11/2025
Perfluorooctanesulfonicacid6:2fts
Detected: 4.8 NG/L (ppt)
6/11/2025
Perfluoroheptanesulfonicacid (PFHPS)
Detected: 5.6 NG/L (ppt)
6/11/2025
Nonafluoronfdha
Detected: 4.7 NG/L (ppt)
6/11/2025
Perfluorohexanesulfonicacid (PFHxS)
Detected: 8.4 NG/L (ppt)
Found at 2 providers
9cl-Pf3ons
Detected: 4.7 NG/L (ppt)
6/11/2025
Perfluoroctanesulfonicacid (PFOS)
Detected: 5.7 NG/L (ppt)
Found at 2 providers
One of two PFAS with an enforceable federal limit (4 ppt) since 2024.
Perfluoroctanoicacid (PFOA)
Detected: 5.7 NG/L (ppt)
Found at 2 providers
One of two PFAS with an enforceable federal limit (4 ppt) since 2024.
Perfluorononanoicacid (PFNA)
Detected: 4.5 NG/L (ppt)
Found at 2 providers
Perfluorodecanesulfonicacid8:2fts
Detected: 4.7 NG/L (ppt)
6/11/2025
Conductivity (at 25°C)
Detected: 463 UMHO/CM
Found at 4 providers
Dichloroaceticacid
Detected: 6.8 UG/L (ppb)
Found at 2 providers
Trichloroaceticacid
Detected: 3.5 UG/L (ppb)
Found at 2 providers
Dibromoaceticacid
Detected: 1.9 UG/L (ppb)
Found at 2 providers
1, 2-Dibromo-3-Chloropropane
Detected: 0.34 UG/L (ppb)
Found at 2 providers
Turbidity
Detected: 1.6 NTU
Found at 2 providers
A measure of water cloudiness from suspended particles.
Adsorbableorganicfluorine
Detected: 3300 NG/L (ppt)
6/17/2025
Perfluorobutanoicacid (PFBA)
Detected: 2.7 NG/L (ppt)
6/17/2025
Color
Detected: 7 UNITS
4/24/2025
Odor
Detected: 1.5 TON
10/9/2025
Perchlorate
Detected: 3.5 UG/L (ppb)
5/6/2025
Can occur naturally or from industrial/military sources; may interfere with thyroid function at elevated levels.
Filtration considerations: General system types, not a specific product recommendation.