Agricultural Well Drilling: Farm Irrigation Wells for San Diego & Riverside Counties

Southern California's diverse agricultural sector — from avocado groves to row crops, nurseries to vineyards — depends on reliable water. With municipal water costs rising and availability uncertain, private agricultural wells provide farmers the water security and cost control essential for sustainable operations.

At Southern California Well Service, we've drilled wells for farms of all sizes across San Diego and Riverside Counties. Here's what you need to know about agricultural well drilling in our region.

Types of Agricultural Wells

Irrigation Wells

The backbone of farm water supply, irrigation wells provide water for crops:

• Drip irrigation: Lower GPM requirements, constant demand during growing season
• Sprinkler systems: Higher instantaneous GPM, often run in zones
• Flood irrigation: Highest GPM demand, less common in our region due to water costs

Livestock Wells

Cattle, horses, and other livestock need reliable daily water:

• Pasture wells: Supply water troughs in grazing areas
• Barn wells: Domestic-style wells for smaller livestock operations
• Feedlot wells: High-capacity systems for concentrated animal operations

Multi-Purpose Farm Wells

Many farms need wells that serve multiple purposes:

• Household use (domestic quality water)
• Crop irrigation
• Livestock watering
• Equipment washing
• Processing operations

Water Requirements by Crop Type

Understanding your water needs is the first step in well planning:

Tree Crops (Common in San Diego County)

Crop	Annual Water (acre-feet)	Peak Daily (gal/acre)
Avocados	3.0-4.5	3,500-4,500
Citrus	2.5-3.5	3,000-4,000
Wine grapes	0.5-1.5	1,500-2,500
Stone fruit	2.5-3.5	3,000-4,000

Row Crops and Vegetables

Crop	Annual Water (acre-feet)	Peak Daily (gal/acre)
Tomatoes	2.0-3.0	3,000-4,000
Strawberries	2.5-3.5	3,500-4,500
Mixed vegetables	2.0-3.0	2,500-3,500
Herbs	1.5-2.5	2,000-3,000

Nursery and Greenhouse

Nurseries have intensive water needs:

• Container nursery: 0.5-1.0 gallons per square foot per day
• Greenhouse: 0.3-0.5 gallons per square foot per day
• Field-grown nursery stock: Similar to row crops

See our dedicated Nursery & Greenhouse Well Guide.

Well Sizing for Agriculture

Calculating Required GPM

To size your agricultural well:

1. Calculate peak daily demand — total gallons needed on hottest irrigation day
2. Determine pumping hours — typically 8-16 hours per day
3. Add storage buffer — storage reduces required GPM

Example: 10-acre avocado grove needs 40,000 gallons on peak day. Pumping 12 hours/day requires 55 GPM minimum. With 20,000-gallon storage tank, could operate with 35-40 GPM well.

GPM Guidelines by Farm Size

Irrigated Acreage	Minimum GPM	Recommended GPM
5-10 acres	25-50	50-75
10-25 acres	50-100	100-150
25-50 acres	100-200	200-300
50-100 acres	200-400	Multiple wells

Agricultural Well Construction

Well Design

Agricultural wells differ from residential wells in several ways:

• Larger diameter: 8-12" casing common (vs. 6" residential)
• Deeper setting: Pump set deeper to handle heavy pumping
• Robust equipment: Industrial-grade pumps rated for continuous operation
• Storage integration: Often paired with large storage tanks

Casing Options

Casing Diameter	Max GPM	Typical Use
6"	50-75	Small farms, livestock
8"	100-200	Medium farms, orchards
10"	200-400	Large farms, intensive irrigation
12"+	400+	Large-scale agriculture

Pump Systems

Agricultural pumps must handle demanding duty cycles:

• Submersible pumps: Most common, efficient, low maintenance
• Line shaft turbines: For very high capacity wells, motor at surface
• Booster pumps: For storage tank systems, pressurize distribution
• VFD controllers: Variable speed drives reduce energy costs 20-40%

Water Quality for Agriculture

Irrigation water quality directly affects crop health and yield:

Key Parameters

Parameter	Good	Moderate	Poor
TDS (ppm)	<500	500-1,500	>1,500
Sodium (SAR)	<3	3-9	>9
Chloride (ppm)	<140	140-350	>350
Boron (ppm)	<0.7	0.7-2.0	>2.0

Crop Sensitivity

Some crops are more sensitive to water quality:

• Highly sensitive: Avocados, citrus, strawberries, beans
• Moderately sensitive: Tomatoes, peppers, most vegetables
• Tolerant: Cotton, barley, sugarbeets (less common in our area)

Always test water quality before planting sensitive crops. See our water testing guide.

Storage Systems

Agricultural storage tanks provide operational flexibility:

Benefits of Storage

• Reduced well size: Store during low-demand periods, use during peak
• Pump protection: Continuous cycling reduces pump life
• Emergency reserve: Buffer during pump repairs
• Fire protection: Required for some rural properties

Sizing Agricultural Storage

• Minimum: 1-2 hours of peak demand
• Recommended: 1 day of average demand
• Optimal: 2-3 days of average demand

Example: Farm using 50,000 gallons/day should have 50,000-150,000 gallon storage.

Regulatory Considerations

County Permits

Both San Diego and Riverside Counties require well permits:

• Well permit application and fees
• Site plan showing setbacks from septic, property lines
• Compliance inspection after completion

SGMA (Sustainable Groundwater Management Act)

Large agricultural wells may face additional requirements under SGMA:

• Well registration: Required in most basins
• Metering: May be required for high-capacity wells
• Extraction fees: Some basins impose pumping fees
• Allocation limits: Critical basins may limit new extraction

We help navigate these requirements as part of your project.

Cost Factors

Drilling Costs

Component	Cost Range
Drilling (per foot)	$50-$100
6" steel casing (per foot)	$25-$40
8" steel casing (per foot)	$40-$60
Development and testing	$2,000-$5,000

Pump and Equipment

System Capacity	Pump + Controls
50-100 GPM	$8,000-$15,000
100-200 GPM	$15,000-$30,000
200-400 GPM	$30,000-$60,000

Total Project Examples

• Small farm (10 acres): $35,000-$60,000 typical
• Medium farm (25 acres): $60,000-$100,000 typical
• Large operation (50+ acres): $100,000-$200,000+

See detailed breakdown: Agricultural Well Cost Guide

ROI: Well vs. Municipal Water

Compare ongoing costs to determine payback:

Municipal Agricultural Water Rates

• San Diego County Water Authority: $1,200-$1,800 per acre-foot
• Fallbrook PUD ag rate: ~$1,000 per acre-foot
• Rainbow MWD: ~$1,100 per acre-foot

Well Water Cost

• Electricity: $100-$300 per acre-foot pumped
• Maintenance: $50-$100 per acre-foot (amortized)
• Total: $150-$400 per acre-foot

Savings: $800-$1,400 per acre-foot compared to municipal water.

A 20-acre avocado operation using 3 acre-feet per acre (60 AF/year) saves $48,000-$84,000 annually with well water. Typical well ROI: 2-5 years.