San Luis Obispo Tap Water Quality Report
San Luis Obispo's water met every enforceable federal limit, but 3 results sit above a health goal at the most-affected of its 3 water systems. For many substances that goal is zero, so the number that matters is the distance to the limit.
Utilities
3 Utilities
People Served
1,326
MCL Violations
0
Last Updated
Is San Luis Obispo Tap Water Safe to Drink?
Read that carefully, because "above a health goal" is the phrase people misread. For many substances the goal is zero, so it can mean "found at all" rather than "too much" — the number that matters is the distance to the enforceable limit, and the table below shows both. Where a finding warrants it, match a certified filter to that contaminant rather than to a "removes 99%" claim.
The data below shows test results from 3 water utilities serving 1,326 people in the San Luis Obispo area. Water quality testing is conducted regularly and reported to the EPA. This report was last updated 2023-11-05.
Boil water advisories are issued by water systems and state agencies, and they change from day to day. Boil water advisories in California
San Luis Obispo Water Service Areas
What these numbers actually mean for San Luis Obispo, CA
We read San Luis Obispo, CA’s published record and send you a short report — which findings warrant a decision, which to ignore, and what to do about it. Including when the answer is nothing.
- 3 contaminants above EPA health goals at its most-affected system
- 81 results across 3 water systems
- No PFAS results on record
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Recommended Water Filters for San Luis Obispo
Based on San Luis Obispo's water quality data, these NSF-certified filters are recommended to remove contaminants above EPA MCLGs.
Culligan
ZeroWater
NSF Certified:
Flow Rate
1.9 gpm
Daily Production
1 gpd
Highlights:
- Compact design
- Easy to set up
- Affordable
- NSF-42, NSF-53, NSF-401 certified
Removes 19 contaminants:
+14 more
Strontium, Molybdenum, Fluoride, Uranium, Lead, Total PFAS, Chlorine, 25, Phosphorus, Bicarbonate, Calcium, Carbonate, Magnesium, Sodium
Whirlpool Corporation
W11256135
NSF Certified:
Capacity
1001 gal
Filter Life
3 mo
Flow Rate
0.7 gpm
Removes 19 contaminants:
+14 more
Benzene, Carbofuran, Chlorine (Free), Chlorine (Total), Chlorine Dioxide, Chlorobenzene, Cryptosporidium, Ethylbenzene, Lead, Mercury, Metolachlor, Tetrachloroethylene, Toxaphene, Turbidity
Whirlpool Corporation
W11569861
NSF Certified:
Capacity
1001 gal
Filter Life
3 mo
Flow Rate
0.52 gpm
Removes 22 contaminants:
+17 more
Atrazine, Benzene, Carbofuran, Chlorine (Free), Chlorine (Total), Chlorine Dioxide, Chlorobenzene, Cryptosporidium, Ethylbenzene, Lead, Mercury, Metolachlor, Styrene, Tetrachloroethylene, Toxaphene, Trichloroethylene, Turbidity
AquaTru
Classic
NSF Certified:
Flow Rate
0.04 gpm
Daily Production
600 gpd
Highlights:
- Best overall contaminant reduction score
- Most performance certifications
- Lifetime warranty
- NSF-42, NSF-53, NSF-58, NSF-401 certified
Removes 23 contaminants:
+18 more
Molybdenum, Barium, Chlorine, Arsenic, 83+ contaminants, Calcium, Chloride, Copper, Magnesium, Nitrate, Phosphorus, Sodium, Sulfate, Total Dissolved Solids, Zinc, Total THMs, Chloroform, Nitrate (as N)
Filters for what San Luis Obispo reported
Verify Your Water Quality with Independent Testing
With 3 contaminants above EPA health guidelines, independent laboratory testing provides a second opinion and can track changes over time.
SimpleLab
Advanced Home Water Test
$269
Comprehensive water analysis testing over 200 contaminants including bacteria, heavy metals, and chemical compounds.
Tap Score
Advanced Microplastics Test
$829
Cutting-edge testing for microplastics particles in drinking water using advanced laboratory techniques.
Tap Score
Haloacetic Acids (HAA9) Test
$275
Tests for disinfection byproducts formed when chlorine reacts with organic matter in water treatment.
With 3 contaminants above health guidelines, you may want to explore water purification options. Learn how to make distilled water at home for applications like humidifiers, CPAP machines, and baby formula.
What San Luis Obispo's water readings can explain
Utility-reported data for San Luis Obispo includes sulfate — the readings behind these common tap water questions. We publish a city-level hardness figure for San Luis Obispo, resolved from its water systems where they report one and estimated from county sampling where they do not. Each page starts with the hot-tap and cold-tap check, then shows what your own water system reported.
On a private well near San Luis Obispo? Public-water results do not apply to private wells. See San Luis Obispo County well water testing and USGS risk data — modeled arsenic, nitrate, and the tests to run.
What a water softener costs for San Luis Obispo's water
San Luis Obispo's tap water measures 12.6 grains per gallon (216.0 mg/L) — very hard on the USGS scale, the range where scale on fixtures and appliances is the usual complaint.
Water softener cost for 12.6 gpg water in San Luis Obispo — equipment and local installation labour for your ZIP code, with the sizing arithmetic shown in full. For the national picture first, read what a water softener costs — equipment, installation labour and ten-year ownership, each separated out.
Frequently Asked Questions About San Luis Obispo Tap Water
San Luis Obispo's water met every enforceable federal limit, but 3 results sit above a health goal at the most-affected of its 3 water systems. For many substances the EPA sets that goal to zero, so "above the goal" can mean "found at all" — the number that matters is the distance to the enforceable limit, and this page shows both.
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