Serving roughly 4,100 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 ATASCADERO STATE HOSPITAL
1 water provider directly on file, serving roughly 4,100 people in San Luis Obispo County, California.
Quick answer: ATASCADERO STATE HOSPITAL has no violations on file and no single reading stands out against its peers (252 other providers in this area). It serves roughly 4,100 people, and the full breakdown below reflects everything EPA and California have on record for it.
Lead Summary
Copper Summary
PFBS
PFHXS
PFOS
PFHXA
Pfpes
Lead
TTHM
Chloroform
Bromoform
Bromodichloromethane
Dibromochloromethane
Dichloroaceticacid
Dibromoaceticacid
Copper, Free
Aggressive Index
Langelier Index (pH(s))
Magnesium
Potassium
Sodium
Hardness, Total (ASCACO3)
Calcium
Alkalinity, Total
Alkalinity, Bicarbonate
TDS
Chloride
Sulfate
Fluoride
Nitrate-Nitrite
Nitrate
Perfluorohexanesulfonicacid (PFHxS)
Perfluoroctanesulfonicacid (PFOS)
Perfluorobutanesulfonicacid (PFBS)
Perfluoropentanesulfonicacid (PFPES)
Turbidity
pH, Field
Manganese
Zinc
Conductivity (at 25°C)
Utility ATASCADERO STATE HOSPITALPopulation served 4,100Owner State or Territorial Government
No violations on file
Contaminants found
Metals
Naturally occurring or corrosion-related elements, e.g. lead, arsenic, copper
Lead Summary
Detected: 0.0045 mg/L (ppm)
12/31/2025
Copper Summary
Detected: 1.64 mg/L (ppm)
12/31/2025
Lead
Detected: 6.1 UG/L (ppb)
6/26/2025
A metal that can leach from old pipes, solder, and fixtures. Current medical guidance holds there is no truly safe level of lead exposure, especially for children and pregnant women.
Copper, Free
Detected: 2.2 UG/L (ppb)
10/14/2025
Manganese
Detected: 0.8 UG/L (ppb)
4/1/2025
Mainly a taste/staining concern at typical levels; long-term neurological research at high chronic exposure is ongoing.
Zinc
Detected: 10 UG/L (ppb)
4/1/2025
Disinfection Byproducts
Formed when chlorine used to disinfect water reacts with organic matter
TTHM
Detected: 26 UG/L (ppb)
9/23/2025
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: 2.4 UG/L (ppb)
9/23/2025
One of the individual trihalomethane disinfection byproducts, formed when chlorine reacts with organic matter.
Bromoform
Detected: 5.9 UG/L (ppb)
9/23/2025
Bromodichloromethane
Detected: 6.2 UG/L (ppb)
9/23/2025
Dibromochloromethane
Detected: 11 UG/L (ppb)
9/23/2025
Inorganics
Common dissolved minerals and salts, e.g. nitrate, fluoride, chloride
Chloride
Detected: 43 MG/L (ppm)
4/1/2025
Sulfate
Detected: 140 MG/L (ppm)
4/1/2025
Fluoride
Detected: 0.2 MG/L (ppm)
4/1/2025
Often added deliberately for dental health; can also occur naturally.
Nitrate-Nitrite
Detected: 0.7 MG/L (ppm)
4/1/2025
Nitrate
Detected: 1.1 MG/L (ppm)
4/8/2025
Commonly from agricultural fertilizer runoff or septic systems. Above the legal limit, it's an immediate concern especially for infants.
Minerals
Everyday minerals that mainly affect taste and water hardness
Magnesium
Detected: 35 MG/L (ppm)
4/1/2025
Potassium
Detected: 1 MG/L (ppm)
4/1/2025
Sodium
Detected: 26 MG/L (ppm)
4/1/2025
Calcium
Detected: 82 MG/L (ppm)
4/1/2025
Properties
General water characteristics like pH, hardness, and cloudiness (turbidity)
Langelier Index (pH(s))
Detected: 0.2 LANG
4/1/2025
Hardness, Total (ASCACO3)
Detected: 349 MG/L (ppm)
4/1/2025
pH, Field
Detected: 7.35 PH
4/1/2025
PFAS & Emerging Contaminants
Human-made "forever chemicals" and other substances not yet fully regulated
PFBS
Detected: 0.0036 µg/L (ppb)
8/15/2023
PFHXS
Detected: 0.0044 µg/L (ppb)
8/15/2023
PFOS
Detected: 0.0043 µg/L (ppb)
8/15/2023
One of two PFAS with an enforceable federal limit (4 ppt) since 2024.
PFHXA
Detected: 0.0036 µg/L (ppb)
2/8/2023
Pfpes
Detected: 0.0061 µg/L (ppb)
2/8/2023
Calculated Parameters
Values worked out mathematically from other test results, not measured directly
Alkalinity, Bicarbonate
Detected: 280 MG/L (ppm)
4/1/2025
Other
Additional substances tested that don't fit neatly into the categories above
Dichloroaceticacid
Detected: 1.3 UG/L (ppb)
9/23/2025
Dibromoaceticacid
Detected: 4.5 UG/L (ppb)
9/23/2025
Aggressive Index
Detected: 12.1 AGGR
4/1/2025
Alkalinity, Total
Detected: 230 MG/L (ppm)
4/1/2025
TDS
Detected: 470 MG/L (ppm)
4/1/2025
Perfluorohexanesulfonicacid (PFHxS)
Detected: 6 NG/L (ppt)
7/9/2025
Perfluoroctanesulfonicacid (PFOS)
Detected: 8.5 NG/L (ppt)
7/9/2025
One of two PFAS with an enforceable federal limit (4 ppt) since 2024.
Perfluorobutanesulfonicacid (PFBS)
Detected: 3.5 NG/L (ppt)
7/9/2025
Perfluoropentanesulfonicacid (PFPES)
Detected: 3.4 NG/L (ppt)
4/8/2025
Turbidity
Detected: 0.1 NTU
4/1/2025
A measure of water cloudiness from suspended particles.
Conductivity (at 25°C)
Detected: 775 UMHO/CM
4/1/2025
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.