CITY OF PASO ROBLES WATER DIVISION Water Quality Report
Serving roughly 31,176 people in San Luis Obispo County, California.
Data current as of July 2026
🔍Straight from EPA
🧪Real Lab Results
📅Updated Quarterly
🏠Local Expertise
Results for CITY OF PASO ROBLES WATER DIVISION
1 water provider directly on file, serving roughly 31,176 people in San Luis Obispo County, California.
Quick answer: CITY OF PASO ROBLES WATER DIVISION has no violations on file. One reading is worth knowing about: Lithium was measured at 40.5µg/L, among the highest of the 252 providers on file in this area. It's the most notable figure in this system's record among its 252 local peers.
Lead Summary
Lithium
PFHXS
PFHXA
PFBS
PFHPA
PFBA
PFOA
PFPEA
Totalhaloaceticacids (HAA5)
TTHM
Chloroform
Bromoform
Bromodichloromethane
Dibromochloromethane
Dichloroaceticacid
Trichloroaceticacid
Dibromoaceticacid
Copper, Free
Arsenic
Magnesium
Potassium
Sodium
Calcium
Hardness, Total (ASCACO3)
Alkalinity, Total
Alkalinity, Bicarbonate
TDS
Sulfate
Chloride
Fluoride
Nitrate
Nitrate-Nitrite
Perfluorobutanesulfonicacid (PFBS)
Perfluorohexanesulfonicacid (PFHxS)
Perfluoroctanesulfonicacid (PFOS)
Perfluoroctanoicacid (PFOA)
Perfluorobutanoicacid (PFBA)
Perfluoroheptanoicacid (PFHPA)
Perfluorohexanoicacid (PFHXA)
Perfluoropentanoicacid (PFPEA)
Perfluoropentanesulfonicacid (PFPES)
Radium-228
Combined Uranium
Gross Alpha Particle Activity
pH
Boron, Total
Vanadium, Total
Iron
Chromium, Hex
Tetrachloroethylene
Perchlorate
Barium
Selenium
Conductivity (at 25°C)
Carbon, Total
Manganese
Turbidity
Odor
Utility CITY OF PASO ROBLES WATER DIVISIONPopulation served 31,176Owner 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: 260 UG/L (ppb)
8/31/2025
Arsenic
Detected: 5.3 UG/L (ppb)
10/14/2025
Occurs naturally in some groundwater. Long-term exposure above the legal limit (10 ppb) has been linked to increased cancer risk and cardiovascular disease.
Combined Uranium
Detected: 3.9 PCI/L
2/11/2025
A naturally occurring radioactive metal. Long-term exposure above the legal limit is associated with kidney effects and increased cancer risk.
Vanadium, Total
Detected: 13 UG/L (ppb)
4/8/2025
Iron
Detected: 110 UG/L (ppb)
10/14/2025
Mostly an aesthetic issue (metallic taste, staining) rather than a health concern at typical levels.
Chromium, Hex
Detected: 0.68 UG/L (ppb)
4/8/2025
Barium
Detected: 160 UG/L (ppb)
4/8/2025
Selenium
Detected: 11 UG/L (ppb)
4/8/2025
Manganese
Detected: 22 UG/L (ppb)
10/14/2025
Mainly a taste/staining concern at typical levels; long-term neurological research at high chronic exposure is ongoing.
Disinfection Byproducts
Formed when chlorine used to disinfect water reacts with organic matter
Totalhaloaceticacids (HAA5)
Detected: 2.6 UG/L (ppb)
8/12/2025
TTHM
Detected: 13.7 UG/L (ppb)
8/12/2025
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: 2.2 UG/L (ppb)
8/12/2025
One of the individual trihalomethane disinfection byproducts, formed when chlorine reacts with organic matter.
Bromoform
Detected: 2 UG/L (ppb)
8/12/2025
Bromodichloromethane
Detected: 4 UG/L (ppb)
8/12/2025
Dibromochloromethane
Detected: 5.5 UG/L (ppb)
8/12/2025
Inorganics
Common dissolved minerals and salts, e.g. nitrate, fluoride, chloride
Sulfate
Detected: 37 MG/L (ppm)
4/8/2025
Chloride
Detected: 66 MG/L (ppm)
4/8/2025
Fluoride
Detected: 0.34 MG/L (ppm)
4/8/2025
Often added deliberately for dental health; can also occur naturally.
Nitrate
Detected: 0.51 MG/L (ppm)
8/19/2025
Commonly from agricultural fertilizer runoff or septic systems. Above the legal limit, it's an immediate concern especially for infants.
Nitrate-Nitrite
Detected: 2.3 MG/L (ppm)
4/8/2025
Boron, Total
Detected: 170 UG/L (ppb)
4/8/2025
Minerals
Everyday minerals that mainly affect taste and water hardness
Magnesium
Detected: 25 MG/L (ppm)
8/21/2025
Potassium
Detected: 2 MG/L (ppm)
8/21/2025
Sodium
Detected: 84 MG/L (ppm)
8/21/2025
Calcium
Detected: 51 MG/L (ppm)
8/21/2025
Properties
General water characteristics like pH, hardness, and cloudiness (turbidity)
Hardness, Total (ASCACO3)
Detected: 240 MG/L (ppm)
4/8/2025
Gross Alpha Particle Activity
Detected: 4.1 PCI/L
8/19/2025
pH
Detected: 7 PH
4/8/2025
A measure of how acidic or basic the water is (7 is neutral). Affects taste and plumbing, not a direct health measure.
PFAS & Emerging Contaminants
Human-made "forever chemicals" and other substances not yet fully regulated
Lithium
Detected: 40.5 µg/L (ppb)
6/18/2025
Occurs naturally in some groundwater. Not currently federally regulated in drinking water.
PFHXS
Detected: 0.004 µg/L (ppb)
6/18/2025
PFHXA
Detected: 0.015 µg/L (ppb)
6/18/2025
PFBS
Detected: 0.0063 µg/L (ppb)
6/18/2025
PFHPA
Detected: 0.0047 µg/L (ppb)
6/18/2025
PFBA
Detected: 0.0061 µg/L (ppb)
12/12/2024
PFOA
Detected: 0.0048 µg/L (ppb)
6/18/2025
One of two PFAS with an enforceable federal limit (4 ppt) since 2024.
PFPEA
Detected: 0.017 µg/L (ppb)
6/18/2025
VOCs (Volatile Organic Compounds)
Industrial solvents and fuel-related chemicals that evaporate easily
Tetrachloroethylene
Detected: 0.59 UG/L (ppb)
8/12/2025
Calculated Parameters
Values worked out mathematically from other test results, not measured directly
Alkalinity, Bicarbonate
Detected: 280 MG/L (ppm)
4/8/2025
Other
Additional substances tested that don't fit neatly into the categories above
Dichloroaceticacid
Detected: 1.1 UG/L (ppb)
8/12/2025
Trichloroaceticacid
Detected: 10 UG/L (ppb)
8/12/2025
Dibromoaceticacid
Detected: 1.5 UG/L (ppb)
8/12/2025
Alkalinity, Total
Detected: 230 MG/L (ppm)
4/8/2025
TDS
Detected: 440 MG/L (ppm)
4/8/2025
Perfluorobutanesulfonicacid (PFBS)
Detected: 4.1 NG/L (ppt)
10/2/2025
Perfluorohexanesulfonicacid (PFHxS)
Detected: 3 NG/L (ppt)
10/2/2025
Perfluoroctanesulfonicacid (PFOS)
Detected: 2.3 NG/L (ppt)
10/2/2025
One of two PFAS with an enforceable federal limit (4 ppt) since 2024.
Perfluoroctanoicacid (PFOA)
Detected: 2.8 NG/L (ppt)
3/13/2025
One of two PFAS with an enforceable federal limit (4 ppt) since 2024.
Perfluorobutanoicacid (PFBA)
Detected: 2.1 NG/L (ppt)
10/2/2025
Perfluoroheptanoicacid (PFHPA)
Detected: 3 NG/L (ppt)
3/13/2025
Perfluorohexanoicacid (PFHXA)
Detected: 6.2 NG/L (ppt)
3/13/2025
Perfluoropentanoicacid (PFPEA)
Detected: 6.4 NG/L (ppt)
3/13/2025
Perfluoropentanesulfonicacid (PFPES)
Detected: 2.2 NG/L (ppt)
3/13/2025
Radium-228
Detected: 0.807 PCI/L
3/25/2025
Perchlorate
Detected: 1.7 UG/L (ppb)
4/8/2025
Can occur naturally or from industrial/military sources; may interfere with thyroid function at elevated levels.
Conductivity (at 25°C)
Detected: 710 UMHO/CM
4/8/2025
Carbon, Total
Detected: 3.3 MG/L (ppm)
10/14/2025
Turbidity
Detected: 0.95 NTU
2/18/2025
A measure of water cloudiness from suspended particles.
Odor
Detected: 1 TON
2/18/2025
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.