Water Quality in San Luis Obispo, CA (93420)
EPA violation data for public water systems serving ZIP code 93420.
Active Health Violations
32 health-based violations found in the past 5 years, with at least one still unresolved. Contaminant levels have exceeded federal safety limits. Consider testing your tap water independently.
More violations than 86% of US ZIP codes.
Based on EPA compliance data. Not a substitute for an official water quality report from your utility.
31,345
Population
40
Water Systems
64
Violations (5yr)
32
Health-Based
Location
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Water Systems Serving This Area (40)
Santa Margarita Recreation Area
San Luis Obispo Water Department
City Of Paso Robles Water Division
Atascadero Mutual Water Co
City Of Arroyo Grande Utilities Division
All resolvedMesa Dunes Mobile Home Estates
Woodland Park Mutual Water Co
10 health-basedLaetitia Vineyard & Winery Inc
Branch Elementary School
Canyon Crest Mutual Benefit Wc
Halcyon Water System
1 health-basedVarian Ranch Mutual Water
Lopez Recreation Area
Greenheart Farms
Ken Mar Gardens
19 health-basedLaguna Negra Mutual Water Co.
All resolvedCenter Of Effort Winery
Talley Farms Labor Housing
H2o, Inc
Ball Tagawa Growers
All resolvedBert'S Diner
1 health-basedGrande Mobile Manor
Rancho Nipomo Water Company
Terra De Oro Water Company
Glendale Square
Mutual Water Association
1 health-basedCrossroads/ House Of Prayer
Biddle Regional County Park
Lopez Canyon Conference Ground - Inactiv
Precision Mutual Water Company
All resolvedOak Park Manor
Phillips 66 Company, Santa Maria Facilit
All resolvedShaver Lake Village Hotel
Lopez Trout Farm - Inactive
Nunes Water Company
Newsom Springs Mutual Water Co
Vista De Las Flores Water
Sweet Springs Mobile Park
Arroyo Grande Mushroom Farm
Union Oil Company - Santa Mari
Contaminants Found
At high levels, nitrate can cause blue baby syndrome in infants.
Missed testing deadlines — not a detection of bacteria.
Lead and copper testing requirement. Lead exposure can cause developmental harm in children.
Lead & Copper Levels
Lead (Pb)
Within limitSampled: Jan 2025
How Does This Compare?
San Luis Obispo (93420) has more violations than 86% of US ZIP codes. The national average is 18.87 violations per ZIP over 5 years. This ZIP has 64.
Recommended Water Filters
Based on health-based violations detected in your area, these filter types are commonly used to address similar contaminants. Consult your water utility's Consumer Confidence Report for the most current data.
Reverse Osmosis System
Highly effective at removing heavy metals, dissolved solids, and a wide range of contaminants. Recommended for homes with lead or arsenic concerns.
Targets:Lead, Copper, Arsenic, Mercury, Cadmium
Look for:NSF/ANSI 58 certified
UV Water Purifier
Uses ultraviolet light to neutralize bacteria, viruses, and parasites without chemicals. Ideal for homes with microbial contamination concerns.
Targets:E. coli, Coliform, Giardia, Cryptosporidium
Look for:NSF/ANSI 55 (Class A) certified
Always look for filters certified by NSF International for the specific contaminants you want to remove. This is general educational information, not an endorsement of any specific product.