California's diverse geology creates dramatic variations in well depths across the state. From shallow coastal wells to deep desert boreholes, understanding regional depth patterns is essential for budgeting drilling projects and setting realistic expectations.

This statistics page provides comprehensive well depth data by California region, county, and geological formation, based on state well logs and drilling records.

Statewide Overview

285 ft
California average domestic well depth
Source: CA DWR 2024
100-800 ft
Typical depth range statewide
Source: Well Log Database
450 ft
Average new well depth (2024)
Source: Driller Reports
+35 ft
Depth increase over past decade
Source: Trend Analysis
2,000+ ft
Deepest domestic wells
Source: Exceptional Cases
50 ft
Shallowest viable wells
Source: Coastal Areas

Northern California

180 ft
Average - Sacramento Valley
Source: Regional Data
250 ft
Average - North Coast (Mendocino, Humboldt)
Source: County Records
320 ft
Average - Shasta/Redding area
Source: County Records
150 ft
Average - North Bay (Sonoma, Napa)
Source: County Records
380 ft
Average - Sierra Foothills (Nevada, Placer)
Source: County Records
Alluvial/volcanic
Primary aquifer types
Source: USGS

Central Valley

220 ft
Average - Central Valley floor
Source: CV-SALTS
180 ft
Average - Northern CV (Yolo, Solano)
Source: Regional Data
250 ft
Average - San Joaquin Valley
Source: Regional Data
350 ft
Average - Tulare Basin
Source: Regional Data
500+ ft
Agricultural wells (deeper)
Source: Farm Bureau
-50 ft/decade
Depth increase trend (overdraft)
Source: DWR Analysis

Bay Area

200 ft
Average - East Bay hills
Source: Alameda County
280 ft
Average - South Bay (Santa Clara)
Source: County Records
350 ft
Average - Peninsula
Source: San Mateo County
150 ft
Average - Marin County
Source: County Records
Limited
Private wells (urban area)
Source: Planning Data
Franciscan
Complex geology
Source: USGS

Central Coast

250 ft
Average - Monterey County
Source: County Records
280 ft
Average - San Luis Obispo County
Source: County Records
320 ft
Average - Santa Barbara County
Source: County Records
180 ft
Average - Salinas Valley floor
Source: MCWRA
Seawater intrusion
Coastal concern
Source: Monterey County
400+ ft
Inland foothill depths
Source: Well Logs

Southern California Coastal

200 ft
Average - Ventura County
Source: County Records
300 ft
Average - Los Angeles County
Source: County Records
250 ft
Average - Orange County
Source: OCWD
320 ft
Average - San Diego coastal
Source: County Records
Managed basins
Most groundwater managed
Source: SWRCB
Limited private wells
Urban development
Source: Planning Data

San Diego County (Detailed)

320 ft
Countywide average
Source: County Well Logs
180 ft
Coastal valleys
Source: Regional Data
280 ft
Inland valleys (Ramona)
Source: Regional Data
420 ft
Foothill communities (Alpine)
Source: Regional Data
500+ ft
Mountain areas (Julian)
Source: Regional Data
Fractured granite
Primary aquifer (backcountry)
Source: USGS

Riverside County (Detailed)

350 ft
Countywide average
Source: County Well Logs
285 ft
Temecula Valley
Source: RCWD
380 ft
Coachella Valley
Source: CVWD
425 ft
Hemet/San Jacinto
Source: EMWD
520 ft
Desert Hot Springs
Source: Regional Data
600+ ft
Palm Desert/Indian Wells
Source: Deep Desert

Desert Regions

450 ft
Average - High Desert (Victorville)
Source: MWA
380 ft
Average - Imperial Valley
Source: IID
320 ft
Average - Mojave (Lancaster)
Source: AV-East GSA
500+ ft
Common in Coachella Valley
Source: CVWD
Dropping levels
Overdraft concerns
Source: SGMA Basins
+75 ft
Depth increase since 2010
Source: Trend Analysis

Mountain & Foothill Regions

400 ft
Average - Sierra Nevada foothills
Source: Regional Data
350 ft
Average - San Bernardino Mountains
Source: County Records
280 ft
Average - Lake Arrowhead area
Source: Local Data
320 ft
Average - Big Bear area
Source: Local Data
15-25 gpm
Typical yield (fractured rock)
Source: Driller Data
Unpredictable
Fracture-dependent
Source: Geology

Frequently Asked Questions

What is the average well depth in California?

The statewide average domestic well depth is 285 feet, but this varies dramatically by region. Sacramento Valley averages 180 feet, while desert areas average 450+ feet. New wells drilled in 2024 averaged 450 feet due to declining water tables. The typical range is 100-800 feet, with depths increasing approximately 35 feet per decade statewide.

Why are California wells getting deeper?

California wells are getting deeper (average +35 feet over the past decade) due to groundwater overdraft, drought conditions, and increased pumping. The Central Valley and desert regions show the greatest depth increases, with some areas requiring wells 50-75 feet deeper than a decade ago. SGMA regulations aim to stabilize water levels by 2040-2042.

How deep are wells in San Diego County?

San Diego County wells average 320 feet deep, with significant variation by area: coastal valleys 180 feet, inland valleys like Ramona 280 feet, foothill communities like Alpine 420 feet, and mountain areas like Julian 500+ feet. The backcountry relies on fractured granite aquifers, which can require deeper drilling to find adequate water.

How deep are desert wells in California?

Desert wells are among the deepest in California. High Desert (Victorville area) averages 450 feet, Coachella Valley 380-600+ feet depending on location, and Imperial Valley 380 feet. Desert areas have seen depth increases of 75+ feet since 2010 due to overdraft. Some Palm Desert properties require wells exceeding 600 feet.

Which California region has the shallowest wells?

Northern California coastal areas and the northern Sacramento Valley have the shallowest wells, averaging 150-180 feet. Sonoma and Napa counties average 150 feet, while parts of the North Coast are even shallower. Coastal plain wells can be as shallow as 50-75 feet where aquifers are close to the surface.

How does geology affect well depth in California?

Geology dramatically affects depth. Alluvial valleys (Central Valley, coastal plains) have shallower, higher-yield wells. Fractured granite (Sierra foothills, San Diego backcountry) requires deeper drilling with unpredictable results. Volcanic areas (Shasta, Lassen) vary widely. Desert sedimentary basins are typically deep with declining water tables.

Need Well Services in Southern California?

Southern California Well Service provides professional well drilling, pump repair, and water testing throughout San Diego, Riverside, and surrounding counties.

📞 Call (760) 463-0493