San Diego County Well Statistics 2026: 52 Facts & Data You Need to Know
📋 In This Guide
San Diego County Well Overview
San Diego County's private water well infrastructure serves thousands of rural and semi-rural properties across the county's diverse terrain—from coastal valleys to mountain communities. Here are the key statistics for 2026:
Source: San Diego County DEH Well Program, California DWR
Well Population by Type
| Well Type | Number of Wells | % of Total |
|---|---|---|
| Domestic/Residential | 19,200 | 67.5% |
| Agricultural/Irrigation | 5,850 | 20.6% |
| Industrial/Commercial | 1,420 | 5.0% |
| Monitoring Wells | 1,280 | 4.5% |
| Public/Community | 700 | 2.4% |
Key San Diego County Well Facts
- 89,000+ residents rely on private wells as their primary drinking water source
- 12.4% of San Diego County's rural population depends on domestic wells
- 4,420 square miles of county area with active well use
- 27 distinct groundwater basins identified in San Diego County
- 247 licensed well drilling contractors serve San Diego County
- Average well age: 31 years
- 18% of domestic wells are over 50 years old
- 34% increase in well permits during 2021 drought year
Wells by Community
Source: San Diego County DEH, 2025
Top 15 San Diego Communities by Well Count
| Rank | Community | Total Wells | Avg Depth (ft) |
|---|---|---|---|
| 1 | Ramona | 4,200 | 285 |
| 2 | Valley Center | 3,800 | 340 |
| 3 | Fallbrook | 2,950 | 265 |
| 4 | Julian/Cuyamaca | 2,100 | 485 |
| 5 | Alpine | 1,850 | 310 |
| 6 | Pauma Valley | 1,680 | 295 |
| 7 | Jamul/Dulzura | 1,520 | 345 |
| 8 | Campo/Potrero | 1,340 | 380 |
| 9 | Descanso | 1,180 | 425 |
| 10 | Pine Valley | 980 | 395 |
| 11 | Lakeside | 920 | 275 |
| 12 | Borrego Springs | 870 | 245 |
| 13 | Bonsall | 780 | 240 |
| 14 | Boulevard | 650 | 365 |
| 15 | Warner Springs | 540 | 320 |
Community Deep Dives
Ramona Valley
- Total wells: 4,200
- Primary aquifer: Ramona Basin (fractured crystalline)
- Average depth: 285 feet
- Typical yield: 8-25 GPM
- Water quality: Generally good; some areas have elevated hardness
- Permit trend: +12% YoY (2025)
Valley Center
- Total wells: 3,800
- Primary aquifer: Pauma/Valley Center Basin
- Average depth: 340 feet
- Typical yield: 5-20 GPM
- Water quality: Variable; iron/manganese in some areas
- Permit trend: +8% YoY (2025)
Julian/Mountain Communities
- Total wells: 2,100
- Primary aquifer: Fractured granite/metamorphic
- Average depth: 485 feet
- Typical yield: 2-10 GPM
- Water quality: Excellent; low TDS
- Challenge: Deeper drilling required; variable yields
Permit Statistics & Trends
Source: San Diego County Department of Environmental Health
Permit Types Issued (2026)
| Permit Type | Number | % of Total |
|---|---|---|
| New Domestic Well | 287 | 62.9% |
| New Agricultural Well | 89 | 19.5% |
| Replacement/Repair | 52 | 11.4% |
| Well Deepening | 18 | 3.9% |
| Monitoring Well | 10 | 2.2% |
10-Year Permit Trend: San Diego County
| Year | Permits | Change | Notes |
|---|---|---|---|
| 2016 | 523 | +28% | Drought peak |
| 2017 | 387 | -26% | Post-drought drop |
| 2018 | 356 | -8% | Normal |
| 2019 | 378 | +6% | Normal |
| 2020 | 412 | +9% | COVID home purchases |
| 2021 | 489 | +19% | Drought spike |
| 2022 | 478 | -2% | High demand continues |
| 2023 | 398 | -17% | Wet year |
| 2024 | 417 | +5% | Recovery |
| 2025 | 456 | +9% | Above average |
Permit Statistics
- Average processing time: 12-18 business days
- Permit fee: $1,247 (domestic well, 2026)
- Denial rate: 2.8% (primarily location/setback issues)
- Required inspections: Minimum 2 (casing, final)
- Water quality test required: Yes, within 30 days of completion
Groundwater & Aquifer Data
Source: California DWR Bulletin 118, San Diego County Water Authority
Major Groundwater Basins in San Diego County
| Basin Name | Area (sq mi) | Storage (AF) | Priority |
|---|---|---|---|
| San Diego River Valley | 52.8 | 145,000 | Medium |
| San Pasqual Valley | 8.4 | 78,000 | Medium |
| Santa Maria Valley | 12.1 | 65,000 | Medium |
| Borrego Valley | 102 | 1,200,000 | Medium (Critical) |
| Warner Valley | 18.5 | 89,000 | Low |
| San Luis Rey Valley | 28.7 | 112,000 | Medium |
| Ramona | 35.2 | 48,000 | Low |
| El Cajon Valley | 14.6 | 42,000 | Low |
Groundwater Level Trends (2021-2026)
| Area | 5-Year Change | 2025 Level | Status |
|---|---|---|---|
| Borrego Valley | -18.2 ft | -285 ft avg | Declining |
| Ramona Basin | -4.8 ft | -125 ft avg | Stable |
| Valley Center | -7.3 ft | -165 ft avg | Moderate decline |
| Fallbrook Area | -3.2 ft | -95 ft avg | Stable |
| Julian/Mountain | -8.9 ft | -210 ft avg | Variable |
| Coastal Basins | -1.4 ft | -45 ft avg | Good |
Aquifer Type Distribution
- Fractured Crystalline Rock: 62% of county (granite, gabbro, metamorphic)
- Alluvial Basins: 23% of county (river valleys, coastal plains)
- Sedimentary Formations: 15% of county (San Diego Formation)
Groundwater Statistics
- Natural recharge rate: ~32,000 acre-feet/year (county average)
- Annual extraction: ~58,000 acre-feet/year
- Overdraft: ~26,000 acre-feet/year deficit
- Borrego Valley overdraft: 5,700 AF/year (most critical)
- Monitoring wells: 287 active USGS/DWR stations
Well Depth Statistics by Area
Source: San Diego County DEH Well Completion Reports
Well Depth by San Diego Region
| Region | Avg Residential | Avg Agricultural | Typical Range |
|---|---|---|---|
| Coastal Valleys | 165 ft | 240 ft | 80-350 ft |
| Inland Valleys (Ramona, Poway) | 285 ft | 380 ft | 150-500 ft |
| North County (Valley Center, Fallbrook) | 305 ft | 425 ft | 180-550 ft |
| East County (Alpine, Lakeside) | 295 ft | 390 ft | 120-480 ft |
| Mountain (Julian, Descanso) | 485 ft | N/A | 250-800 ft |
| Desert (Borrego) | 245 ft | 420 ft | 100-600 ft |
| South County (Jamul, Campo) | 365 ft | 480 ft | 200-650 ft |
Well Depth Trends
- Average depth increased 38 feet over the past decade in San Diego County
- Mountain areas show highest increase: +67 feet since 2015
- 8% of new wells drilled in 2025 exceeded 500 feet
- Deepest domestic well: 1,240 feet (Julian area, 2023)
- Shallowest productive wells: 60-80 feet in coastal alluvial areas
Yield Statistics by Depth
| Depth Range | % of Wells | Avg Yield (GPM) |
|---|---|---|
| 0-150 ft | 12% | 18 GPM |
| 150-300 ft | 38% | 12 GPM |
| 300-450 ft | 32% | 8 GPM |
| 450-600 ft | 14% | 5 GPM |
| 600+ ft | 4% | 3 GPM |
Drilling Costs by Region (2026)
Source: SCWS industry data, local contractor surveys
Well Costs by San Diego Area
| Area | Low | Average | High |
|---|---|---|---|
| Ramona | $28,000 | $38,500 | $65,000 |
| Valley Center | $32,000 | $45,000 | $75,000 |
| Fallbrook | $26,000 | $36,000 | $58,000 |
| Julian/Mountain | $45,000 | $62,000 | $95,000 |
| Alpine | $30,000 | $42,000 | $68,000 |
| Jamul/Dulzura | $35,000 | $48,000 | $78,000 |
| Borrego Springs | $28,000 | $40,000 | $65,000 |
Cost Per Foot by Geology
| Geology Type | Drilling $/ft | Common Locations |
|---|---|---|
| Alluvium/Sand | $35-50 | Coastal valleys, river beds |
| Decomposed Granite | $45-65 | Ramona, Alpine, Lakeside |
| Hard Granite | $65-85 | Julian, Mountain areas |
| Metamorphic | $55-75 | Valley Center, Pauma |
| Mixed/Variable | $50-70 | Most backcountry areas |
Cost Trends
- 22% increase in average well costs from 2022 to 2026
- Steel casing: Up 28% since 2023
- Labor rates: Increased 15% (2024-2026)
- Permit fees: $1,247 (up from $987 in 2022)
- Water testing: $185-450 depending on panel
Water Quality Statistics
Source: GAMA Program, State Water Board
Common Water Quality Issues by Area
| Issue | % of Wells Affected | Common Areas |
|---|---|---|
| Hard Water (>180 mg/L) | 42% | County-wide |
| Iron (>0.3 mg/L) | 18% | Valley Center, Ramona |
| Manganese (>0.05 mg/L) | 14% | Mountain areas |
| Nitrates (>5 mg/L) | 8% | Agricultural areas |
| Coliform Bacteria | 6% | Variable (older wells) |
| Arsenic (>5 ppb) | 3% | Localized areas |
Water Quality by Region
- Julian/Mountain: Excellent quality, low TDS (150-350 mg/L)
- Ramona: Good quality, moderate hardness (200-400 mg/L)
- Valley Center: Variable; iron/manganese treatment often needed
- Fallbrook: Generally good; some nitrate in agricultural areas
- Borrego: Good quality but declining due to overdraft
📊 Data Sources & Methodology
This statistics page compiles data from the following official sources:
- San Diego County Department of Environmental Health - Well Program permit records, inspection data
- California Department of Water Resources (DWR) - Well Completion Report Database, Bulletin 118
- U.S. Geological Survey (USGS) - Groundwater Watch, Water Quality Data
- San Diego County Water Authority - Regional water planning data
- State Water Resources Control Board - GAMA Program water quality data
- Southern California Well Service - Industry cost data from 20+ years of local experience
Data Collection Period: Statistics reflect data collected through January 2026. Historical trends span 2016-2025.
Geographic Scope: All data is specific to San Diego County, California.
Limitations: Well completion reports are self-reported by contractors. Some older wells pre-dating permit requirements may not be in county databases. Cost estimates vary based on site-specific conditions.
Updates: This page is updated quarterly as new county and state data becomes available.
Frequently Asked Questions
How many private wells are in San Diego County?
San Diego County has approximately 28,450 registered private water wells as of 2026. Of these, about 19,200 are active domestic wells serving residential properties, primarily in rural communities like Ramona, Valley Center, Fallbrook, Julian, and Alpine.
What is the average well depth in San Diego County?
The average residential well depth in San Diego County is 320 feet. However, depths vary significantly: coastal valleys average 165 feet, inland valleys 285 feet, and mountain areas often require wells exceeding 485 feet due to the fractured granite geology.
How much does it cost to drill a well in San Diego County?
The average cost for a complete residential well system in San Diego County in 2026 is $42,500. Costs range from $26,000 for shallow wells in favorable areas like Fallbrook to over $95,000 for deep wells in hard rock formations like Julian. Drilling alone costs $35-85 per foot depending on geology.
Which San Diego communities have the most private wells?
Ramona leads with approximately 4,200 private wells, followed by Valley Center (3,800), Fallbrook (2,950), Julian/Cuyamaca (2,100), and Alpine (1,850). These communities rely heavily on groundwater due to limited municipal water infrastructure.
What is the current groundwater trend in San Diego County?
San Diego County groundwater levels have declined an average of 6.8 feet over the past 5 years (2021-2026). The Borrego Valley shows the most significant decline (-18.2 feet) and is classified as critically overdrafted. Coastal basins remain relatively stable due to recharge programs.
Need Well Service in San Diego County?
Southern California Well Service has been serving San Diego County communities for over 20 years. We know the local geology, aquifers, and what it takes to drill successful wells in Ramona, Valley Center, Fallbrook, Julian, Alpine, and throughout the backcountry.
Call us today: (760) 440-8520
