Water Quality in Napa, CA (94558)
EPA violation data for public water systems serving ZIP code 94558.
Active Health Violations
17 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 94% of US ZIP codes.
Based on EPA compliance data. Not a substitute for an official water quality report from your utility.
63,657
Population
123
Water Systems
82
Violations (5yr)
17
Health-Based
Location
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Water Systems Serving This Area (123)
Napa, City Of
Surface water 84,804 people served
0 violations
Lead tested: 0 ppb (limit: 15 ppb) ✓
American Canyon, City Of
Surface water 21,437 people served
0 violations
Lead tested: 0 ppb (limit: 15 ppb) ✓
Phelps Vineyards
Groundwater 19,412 people served
0 violations
Rancho Monticello Resort
Surface water 2,900 people served
0 violations
Lake Berryessa Marina Resort - Inactive
Surface water 2,000 people served
0 violations
Napa-Berryessa Resort
Surface water 1,150 people served
0 violations
South Shore Resort
Surface water 1,000 people served
0 violations
Spanish Flat Calif Water Dist
Surface water 700 people served
0 violations
Circle Oaks Water District
Surface water 500 people served
0 violations
Chimney Rock Golf Course
Groundwater 500 people served
0 violations
Napa Valley Country Club
1 health-based Groundwater 400 people served
2 violations (5yr)
· 1 health-based
Lead tested: 0 ppb (limit: 15 ppb) ✓
Basalt Rock Company
Groundwater 400 people served
0 violations
Hillside Christian Center Water System
Groundwater 311 people served
0 violations
Mt George School
Groundwater 275 people served
0 violations
Berryessa Pines Water System
1 health-based Surface water 261 people served
5 violations (5yr)
· 1 health-based
Lead tested: 0 ppb (limit: 15 ppb) ✓
Pueblo Trailer Park - Inactive
Groundwater 255 people served
0 violations
Silverado Pines Mobile Home
Groundwater 255 people served
0 violations
Meyers Water Co.
1 health-based Groundwater 250 people served
2 violations (5yr)
· 1 health-based · All resolved
Lead tested: 6.8 ppb (limit: 15 ppb) ✓
Lake Berryessa Park
Surface water 250 people served
0 violations
Hess Winery
1 health-based Groundwater 250 people served
3 violations (5yr)
· 1 health-based
Lead tested: 0 ppb (limit: 15 ppb) ✓ Copper tested: 1700 ppb (limit: 1300 ppb)
Spanish Flat Water District
1 health-based Surface water 230 people served
5 violations (5yr)
· 1 health-based
Lead tested: 0 ppb (limit: 15 ppb) ✓
Enchanted Hills
Surface water 206 people served
0 violations
Putah Canyon Campground
Groundwater 200 people served
0 violations
Silverado Pines Mobilehome
Groundwater 200 people served
0 violations
Welcome Grange Hall
1 health-based Groundwater 200 people served
5 violations (5yr)
· 1 health-based · All resolved
Bell Wine Cellars
Groundwater 200 people served
0 violations
Sugarloaf Park
Groundwater 200 people served
0 violations
Syar Industries
Groundwater 180 people served
0 violations
Chateau Potelle
Groundwater 150 people served
0 violations
Silver Pony School
Groundwater 150 people served
0 violations
Turtle Rock Water Supply
Groundwater 150 people served
0 violations
Syar Industries
Groundwater 130 people served
0 violations
Lead tested: 19 ppb (limit: 15 ppb)
Carneros School
Groundwater 125 people served
0 violations
Chimney Rock Winery
All resolved Groundwater 122 people served
1 violation (5yr)
· All resolved
Lewis Cellars
All resolved Groundwater 119 people served
1 violation (5yr)
· All resolved
Baldacci Family Vineyards
Groundwater 110 people served
0 violations
One Hope Winery
Groundwater 110 people served
0 violations
Pleasure Cove Resort
Groundwater 106 people served
0 violations
Laird Wine Studio
All resolved Groundwater 106 people served
1 violation (5yr)
· All resolved
Vineyard Knolls Golf Course
Groundwater 100 people served
0 violations
Nvusd: Stonebridge School
Groundwater 100 people served
0 violations
Lead tested: 33 ppb (limit: 15 ppb)
Wild Horse Valley Ranch
1 health-based Groundwater 100 people served
2 violations (5yr)
· 1 health-based · All resolved
The Oaks
Groundwater 100 people served
0 violations
Clos Du Val Wine Co.
Groundwater 100 people served
0 violations
Odd Fellow Park (Chg. District)
Groundwater 100 people served
0 violations
Mt. George Estates
All resolved Groundwater 100 people served
1 violation (5yr)
· All resolved
Gene Norris Plaza
All resolved Groundwater 100 people served
1 violation (5yr)
· All resolved
Altamura Winery
Groundwater 100 people served
0 violations
Nvusd: Carneros School
Groundwater 100 people served
0 violations
Lead tested: 16 ppb (limit: 15 ppb)
Nvusd: Wooden Valley School
Groundwater 100 people served
0 violations
Nvusd: Capell Valley School
Groundwater 100 people served
0 violations
Piazza Winery
Groundwater 99 people served
0 violations
Z D Wines
Groundwater 95 people served
0 violations
Lead tested: 0 ppb (limit: 15 ppb) ✓
Church Of Christ
Groundwater 80 people served
0 violations
Berryessa Park Water Co
Groundwater 80 people served
0 violations
Artesa Vineyards & Winery
Groundwater 76 people served
0 violations
Lead tested: 0 ppb (limit: 15 ppb) ✓
A-1 Market
Groundwater 75 people served
0 violations
Soscol Liquor & Deli
Groundwater 75 people served
0 violations
Pine Ridge Winery
1 health-based Groundwater 75 people served
1 violation (5yr)
· 1 health-based · All resolved
Lead tested: 3.3 ppb (limit: 15 ppb) ✓
St. Andrews Winery
Groundwater 75 people served
0 violations
Atlas Peak Grill
Groundwater 75 people served
0 violations
B Cellars Winery
Groundwater 74 people served
0 violations
River Ranch Farm Worker Center
Groundwater 66 people served
0 violations
Mondavi Farm Worker Center
Groundwater 66 people served
0 violations
Cosentino Winery
Groundwater 65 people served
0 violations
Calistoga Farm Worker Center
Groundwater 65 people served
0 violations
Conn Creek Winery
Groundwater 64 people served
0 violations
Sunrise Montessori Of Napa
Groundwater 60 people served
0 violations
Laird Family Estate
1 health-based Groundwater 55 people served
5 violations (5yr)
· 1 health-based
Lead tested: 0 ppb (limit: 15 ppb) ✓
French Wine Embassy, Inc
Groundwater 50 people served
0 violations
Wilcoxsons Resort
Groundwater 50 people served
0 violations
Lokoya Mt Lodge
Groundwater 50 people served
0 violations
Sunrise Montessori School
Groundwater 50 people served
0 violations
Los Arroyos Golf Course
Groundwater 50 people served
0 violations
Chevron Service
Groundwater 50 people served
0 violations
Etude Wines
1 health-based Groundwater 50 people served
3 violations (5yr)
· 1 health-based · All resolved
Lead tested: 0 ppb (limit: 15 ppb) ✓
Wooden Valley School
Groundwater 50 people served
0 violations
Materra Winery
Groundwater 49 people served
0 violations
Sharon S Water System
Groundwater 45 people served
0 violations
Black Stallion Winery
All resolved Groundwater 45 people served
1 violation (5yr)
· All resolved
Rombauer Sierra Foothills
Groundwater 44 people served
0 violations
Milton Road Water Company
1 health-based Groundwater 44 people served
2 violations (5yr)
· 1 health-based
Lead tested: 0 ppb (limit: 15 ppb) ✓
Stags Leap Wine Cellars
Groundwater 40 people served
0 violations
Lead tested: 0 ppb (limit: 15 ppb) ✓
Little Lake Mobile Home Park
All resolved Groundwater 38 people served
1 violation (5yr)
· All resolved
Di Rosa Art Preserve
All resolved Groundwater 37 people served
1 violation (5yr)
· All resolved
U.S. Bureau Of Reclamation-Lk. Berryessa
Surface water 37 people served
0 violations
Stags Leap Winery
All resolved Groundwater 32 people served
2 violations (5yr)
· All resolved
Lead tested: 0 ppb (limit: 15 ppb) ✓
Breezy Resort
Groundwater 30 people served
0 violations
Espinoza Water System
All resolved Groundwater 30 people served
10 violations (5yr)
· All resolved
Monticello School
Groundwater 30 people served
0 violations
Capell Valley School
Groundwater 30 people served
0 violations
Country Inn, The
All resolved Groundwater 29 people served
3 violations (5yr)
· All resolved
R Ranch At The Lake
1 health-based Groundwater 28 people served
5 violations (5yr)
· 1 health-based
Lead tested: 0 ppb (limit: 15 ppb) ✓
Jarvis Vineyard
All resolved Groundwater 27 people served
1 violation (5yr)
· All resolved
Del Dotto Winery
Groundwater 27 people served
0 violations
Silenus Vintners
All resolved Groundwater 25 people served
2 violations (5yr)
· All resolved
Ashes & Diamonds Winery
Groundwater 25 people served
0 violations
Lead tested: 0 ppb (limit: 15 ppb) ✓
William Hill Winery
All resolved Groundwater 25 people served
1 violation (5yr)
· All resolved
Lead tested: 3.2 ppb (limit: 15 ppb) ✓
Hagafen Cellars
1 health-based Groundwater 25 people served
2 violations (5yr)
· 1 health-based · All resolved
Turtle Rock
All resolved Groundwater 25 people served
2 violations (5yr)
· All resolved
Kountry Kitc Hen
Groundwater 25 people served
0 violations
Mira Winery
Groundwater 25 people served
0 violations
Italics Winery
Groundwater 25 people served
0 violations
Kenzo Winery
1 health-based Groundwater 25 people served
2 violations (5yr)
· 1 health-based · All resolved
Mt La Salle Vineyards
Groundwater 25 people served
0 violations
Burgess Cellars
All resolved Groundwater 25 people served
1 violation (5yr)
· All resolved
Shadybrook Estates Winery
Groundwater 25 people served
0 violations
Rexford Mobile Home Estates
Groundwater 25 people served
0 violations
11:11 Winery
Groundwater 25 people served
0 violations
Soscol House
Groundwater 25 people served
0 violations
Napa County Maintenance Yard
Groundwater 25 people served
0 violations
Sequoia Grove Vineyards
1 health-based Groundwater 25 people served
3 violations (5yr)
· 1 health-based
Lead tested: 0 ppb (limit: 15 ppb) ✓
Antinori California
All resolved Groundwater 25 people served
1 violation (5yr)
· All resolved
Darioush Winery
1 health-based Groundwater 25 people served
2 violations (5yr)
· 1 health-based
Lead tested: 0 ppb (limit: 15 ppb) ✓
Mayacamas Vineyards
1 health-based Groundwater 25 people served
2 violations (5yr)
· 1 health-based · All resolved
Biale Winery
Groundwater 25 people served
0 violations
Palmaz Vineyards
Groundwater 24 people served
0 violations
Blue Tip Trailer Park Water
Groundwater 24 people served
0 violations
Napa State Hospital-Camp Coombs
Groundwater under influence of surface water 15 people served
0 violations
Gerald Mcclaine
Groundwater 7 people served
0 violations
Lakeside Market
Groundwater 0
0 violations
Rancho Monticello Resort
Surface water 0
0 violations
Syar Industries Inc./Green Tree Golf
Groundwater 0
0 violations
Contaminants Found
Revised Total Coliform RuleHealth-Based
Missed testing deadlines — not a detection of bacteria.
30 violations
All resolved
LEAD AND COPPER RULE REVISIONSHealth-Based
18 violations
Has active
NitrateHealth-Based
At high levels, nitrate can cause blue baby syndrome in infants.
13 violations
All resolved
SeleniumHealth-Based
1 violation
All resolved
BromateHealth-Based
1 violation
All resolved
Lead and Copper RuleMonitoring
Lead and copper testing requirement. Lead exposure can cause developmental harm in children.
17 violations
Has active
Consumer Confidence RuleMonitoring
Annual water quality report delivery requirement.
1 violation
All resolved
E. COLIMonitoring
1 violation
All resolved
Lead & Copper Levels
Lead (Pb)
Within limit0 ppb measured
Action level: 15 ppb
Sampled: Jul 2025
Copper (Cu)
Exceeds limit1700 ppb measured
Action level: 1300 ppb
Sampled: Jul 2025
How Does This Compare?
Napa (94558) has more violations than 94% of US ZIP codes. The national average is 18.87 violations per ZIP over 5 years. This ZIP has 82.
Fewer violations 94th percentile More violations
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.