Tapcensus

Water quality in Deer Park, California

Deer Park is in Napa County. 188 active public water systems serve the county; 56 had an EPA violation in the past three years.

Most likely your provider

Howell Mountain Mutual Water Company CA2810001 · Community water system · Surface water
Serves 1,244 people Rules violated, past 3 years 0 Distance 2.2 mi

Your location is within the outer bounds of this system's EPA service area.

View system details EPA facility report

Other community water systems in Napa County

27 systems, nearest first
SystemServesStatusRules violated, 3 yrDistance
Adventist Health St. Helena Hospital
 617 0 0.6 mi
Vailima Estates Mutual Water
 25 0 1.0 mi
Linda Vista Mutual Water CO
 90 0 1.2 mi
LA Tierra Heights Mutual
 67 2 1.8 mi
Linda Falls Terrace Mutual
 35 0 1.9 mi
St. Helena, City of
St. Helena		 5,386 2 2.1 mi
River Ranch Farm Worker Center
 66 0 2.9 mi
Pacific Union College
 758 0 3.1 mi
Tucker Acres Mutual Water Co.
 200 1 3.5 mi
Calistoga Farm Worker Center
 67 0 3.9 mi
Calistoga, City of
Calistoga		 5,610 2 7.4 mi
Town of Yountville
 2,785 0 11.1 mi
Veterans Home of California
 1,000 1 11.3 mi
Berryessa Pines Water System
 261 2 11.5 mi
Berryessa Estates (lbrid)
 474 0 12.2 mi
Mondavi Farm Worker Center
 66 0 12.4 mi
Spanish Flat Water District
 92 2 13.2 mi
R Ranch at the Lake
 20 2 13.4 mi
Hess Winery
 100 2 14.4 mi
Berryessa Highlands
 715 1 15.4 mi
Capell Valley Estates
 208 2 16.0 mi
Circle Oaks Water District
 500 0 16.4 mi
Napa, City of
Napa		 84,804 0 18.4 mi
Napa River Ranch
 70 5 22.9 mi
Milton Road Water Company
 39 1 23.9 mi
All 28 community water systems in Napa County
Non-community systems in Napa County (160: schools, campgrounds, workplaces, restaurants)

These systems serve places you visit rather than homes.

SystemServesStatusRules violated, 3 yrUnresolved
Duckhorn Vineyards
 25 0 0
Hunnicutt Winery
 35 0 0
Napa Valley Reserve Water System
 49 1 0
Markham Vineyards
 38 0 0
Rombauer Vineyards
 50 0 0
Wine Country Inn
 60 1 1
Ehlers Estate
 42 0 0
Titus Winery
 64 0 0
Beringer Vineyards
 300 0 0
Trinchero Winery
 263 0 0
St. Helena Purlieu LLC
 25 0 0
Pcsh, LLC
 25 0 0
Cairdean Winery
 30 1 0
Fantesca Winery
 41 0 0
Mending Wall Winery
 37 0 0
Cal Fire Sonoma-Lake-Napa Unit HQ
 65 0 0
Lmr Main Street Partners LLC
 26 0 0
Csp Bale Grist Mill State Historic Par
 185 0 0
Phelps Vineyards
 56 0 0
Rancho la Jota
 40 0 0
Sutter Home Winery
 244 0 0
Frank Family Vineyards
 25 0 0
Davis Estates
 84 0 0
Larkmead Vineyards
 31 0 0
V. Sattui Winery
 45 2 1
Howell Mountain School
 100 1 1
O'shaughnessy Winery
 31 0 0
Wheeler Farms Winery
 43 0 0
Milat Winery
 128 0 0
Robert Keenan Winery
 48 0 0
The Ranch Winery
 200 1 1
William Hill Winery
 25 1 0
Del Dotto Winery
 27 0 0
Cathiard Family Estate Winery
 75 0 0
Schramsberg Winery
 65 0 0
Raymond Vineyard & Cellar
 90 1 1
Castello DI Amorosa
 98 1 1
Outpost Wines
 30 0 0
Csp-Bothe-Napa Valley State Park
 586 0 0
Rutherford Hill Mutual Water
 232 0 0
Whitehall Lane Winery
 45 0 0
Quintessa Winery Water System
St. Helena 		33 0 0
Tpwc Dba the Prisoner Wine Company
 200 0 0
Rutherford Hill Winery
 30 2 1
Kathryn Hall Winery
 28 0 0
Upper Valley Disposal Service
 52 0 0
Round Hill Winery
 100 0 0
Behrens Family Winery
 39 0 0
Sterling Vineyards
 500 0 0
Pestoni Family Estate Winery
 26 0 0
All non-community systems
About this data

Water systems are matched to Napa County, nearest to Deer Park first. Your exact provider depends on your address and connection; the largest community water system in a county is usually the city or town utility. Distances are measured to the centre of the service area EPA publishes for the system or, for systems without one, to the centre of the first town EPA lists the system as serving, from Census Bureau place files.

Town locations and ZIP code areas come from U.S. Census Bureau 2020 files.

Source: the U.S. EPA's Enforcement and Compliance History Online system (ECHO), which publishes the federal Safe Drinking Water Information System. EPA's terms and values are shown as published. The California records are from EPA's data refresh of Oct 7, 2026; EPA refreshes this data quarterly, and states report to EPA with a lag of three to six months, so the newest violations may not appear yet. Retrieved from ECHO on Oct 11, 2026.