By SCWS Team
Published February 1, 2026 · 14 min read
200 feet underground. 50°F water. Running 24/7 for 15 years. That's what you're asking from your submersible pump. It's arguably the hardest-working piece of equipment you own—and the one you think about least. Until it fails.
This comprehensive guide covers everything from basic operation to sizing, installation, maintenance, and costs specific to Southern California wells. Whether you're replacing an aging pump, drilling a new well, or troubleshooting problems, understanding how these remarkable devices work will help you make informed decisions.
Why Brand Matters Underground
Replacing a submersible pump costs $1,500-4,000—mostly labor. A $200 savings on a cheap pump that fails in 7 years instead of 15 will cost you an extra $2,000+ in replacement labor. Buy quality once.
How Submersible Well Pumps Work
Unlike jet pumps that sit above ground and pull water up, submersible pumps are installed deep inside your well casing, completely submerged in water. This design offers several advantages that make submersibles the preferred choice for most residential wells, especially those deeper than 25 feet.
Basic Operating Principle
A submersible pump is essentially a long, cylindrical unit containing a sealed motor at the bottom and a series of impellers (rotating fan-like discs) above. Here's how the system works:
- Motor activation: When your home's pressure drops below the set point (typically 30-40 PSI), the pressure switch signals the pump to turn on
- Impeller rotation: The electric motor spins a series of stacked impellers at high speed
- Water pressurization: Each impeller adds velocity and pressure to the water, pushing it upward through the pump housing
- Water delivery: Pressurized water travels up through the drop pipe to your pressure tank and home
- Check valve protection: A check valve at the pump outlet prevents water from flowing back down when the pump stops
- Cycle completion: Once pressure reaches the high set point (50-60 PSI), the pressure switch turns off the pump
Why Submersible Design Is Superior
Submersible pumps push water rather than pull it, which is inherently more efficient. Key advantages include:
- No priming required: Always submerged means instant water on startup
- Greater depth capability: Can lift water from 400+ feet (jet pumps max out around 110 feet)
- Higher efficiency: 50-70% efficiency vs 25-40% for jet pumps
- Quieter operation: All noise is deep underground
- Self-cooling: Surrounding water keeps the motor cool
- Freeze protection: Below frost line, protected from winter temperatures
Types of Submersible Well Pumps
Submersible pumps come in several configurations to match different well depths, water demands, and applications. Understanding the types helps you choose the right pump for your situation.
By Motor Configuration
2-Wire Submersible Pumps
These pumps have all starting components built into the motor itself. The "2-wire" refers to the power wires (plus ground) running from the control box to the pump.
- Pros: Simpler installation, fewer components to fail above ground, reliable starting in cold weather
- Cons: More expensive, if motor fails the entire pump must be pulled, components harder to service
- Best for: Deeper wells, harder-to-access installations, cold climates
3-Wire Submersible Pumps
These pumps use an external control box (containing capacitors and relay) mounted near the pressure tank. Three wires (plus ground) connect the control box to the pump.
- Pros: Less expensive pump, control box accessible for troubleshooting/repair, capacitor replacement is easy
- Cons: More components, control box can fail, slightly more complex wiring
- Best for: Accessible wells, budget-conscious installations, areas with easy service access
By Application Type
| Type | Best For | Typical Specs |
|---|---|---|
| Standard Residential | Homes with 1-3 bathrooms | 1/2 - 1 HP, 5-15 GPM |
| High-Capacity Residential | Large homes, irrigation | 1.5 - 3 HP, 15-30 GPM |
| Agricultural/Commercial | Farms, ranches, light commercial | 3 - 10+ HP, 30-100+ GPM |
| Variable Speed (VFD) | Constant pressure systems | Various HP, adjustable GPM |
| Stainless Steel | Corrosive water, high quality | Various—premium builds |
Variable Frequency Drive (VFD) Pumps
VFD submersible pumps represent the latest technology in residential well systems. Instead of running at full speed and cycling on/off, VFD pumps adjust motor speed to match water demand, maintaining constant pressure. Learn more in our complete VFD pump guide.
Submersible Pump Sizing Guide
Proper sizing is critical for pump performance and longevity. An undersized pump won't meet your water needs, while an oversized pump wastes energy, cycles excessively, and may damage your well. Here's how to determine the right size.
Key Sizing Factors
1. Well Depth and Static Water Level
The pump must push water from its position deep in the well up to your home. Key measurements:
- Total well depth: Distance from surface to well bottom
- Static water level: Water depth when pump is off
- Pumping water level: How far water drops during pumping (drawdown)
- Pump setting depth: Where the pump is installed (usually 10-20 feet above bottom)
2. Total Dynamic Head (TDH)
TDH measures the total resistance the pump must overcome, including:
- Vertical lift from pumping water level to pressure tank
- Pressure required at the tank (typically 50-60 PSI = 115-138 feet of head)
- Friction losses in pipes and fittings
- Elevation difference between well and house
Example: 200-foot well with 100-foot pumping level, 50 PSI tank pressure, plus 15 feet friction = TDH of approximately 230 feet
3. Required Flow Rate (GPM)
Calculate based on peak household demand and well yield:
- Typical fixture flow: 2-4 GPM per fixture running simultaneously
- Household rule of thumb: 5 GPM for first bathroom, 3 GPM for each additional
- Irrigation adds significant demand (varies widely)
- Critical: Flow rate must not exceed well yield!
Sizing Chart by Well Depth
| Well Depth | Typical HP | Expected GPM | Notes |
|---|---|---|---|
| 50-150 feet | 1/2 HP | 5-10 GPM | Small households, low demand |
| 100-200 feet | 3/4 HP | 8-12 GPM | Typical residential |
| 150-300 feet | 1 HP | 10-15 GPM | Larger homes, moderate demand |
| 200-400 feet | 1.5 HP | 12-20 GPM | High demand, irrigation |
| 300-500+ feet | 2+ HP | 15-30+ GPM | Deep wells, heavy use |
*These are general guidelines. Actual sizing requires calculating TDH, matching pump curves, and considering well yield. See our detailed pump sizing guide for complete calculations.
Installation Considerations
Submersible pump installation is a specialized job requiring proper equipment, safety precautions, and knowledge of well systems. Here's what's involved:
Components Needed
- Submersible pump: Matched to well depth and water demand
- Drop pipe: Polyethylene or PVC pipe connecting pump to surface (sized to pump output)
- Pump cable: Submersible wire rated for underwater use
- Torque arrestor: Prevents pump twisting on startup (see our torque arrestor guide)
- Check valve: Built-in or in-line to prevent backflow
- Pitless adapter: Connects drop pipe to horizontal line below frost level
- Safety rope: Stainless steel cable as backup support
- Pressure tank: Stores water and maintains system pressure
- Control box: For 3-wire pumps; manages starting capacitor
- Pressure switch: Controls pump on/off cycles
Installation Process Overview
- Safety preparation: Shut off power, secure work area, gather equipment
- Remove old pump: Use pump puller or rig to carefully extract existing equipment
- Inspect well: Check casing, measure water level, verify well condition
- Prepare new pump: Attach torque arrestor, connect drop pipe and wire
- Lower pump: Carefully feed pump into well to proper depth
- Connect pitless adapter: Secure connection at frost-line depth
- Wire electrical: Connect pump wire to control box and power supply
- Test system: Prime if needed, check pressure, verify operation
- Adjust settings: Set pressure switch cut-in/cut-out points
- Secure wellhead: Install sanitary cap, ensure proper sealing
⚠️ Safety Warning
Submersible pump installation involves high-voltage electricity near water, heavy equipment, confined space hazards, and risk of well contamination. We strongly recommend professional installation. Improper installation can void warranties, damage equipment, contaminate water supplies, or cause serious injury.
Maintenance and Lifespan
While submersible pumps are designed to run for years without intervention, proper maintenance maximizes lifespan and prevents costly failures.
Expected Lifespan
- Budget pumps: 6-10 years
- Quality residential pumps: 10-15 years
- Premium pumps (Grundfos, Franklin): 15-25 years
- Commercial/industrial: 8-15 years (heavier use)
Lifespan is heavily influenced by water quality (sediment and minerals accelerate wear), proper sizing (oversized pumps cycle excessively), and electrical supply quality.
Maintenance Tasks
Annual checks (homeowner):
- Monitor water pressure and flow for changes
- Check electrical consumption (sudden increases signal problems)
- Listen for unusual cycling patterns
- Test pressure tank pre-charge
- Inspect visible electrical connections
Professional service (every 3-5 years):
- Complete well inspection
- Amp draw testing on pump motor
- Water level measurements
- Flow rate testing
- Pressure tank evaluation
Signs of Pump Problems
Watch for these warning signs that indicate pump issues:
- Reduced pressure/flow: Worn impellers, dropping water level, or clogged screens
- Constant running: Failing pump, major leak, or tank problems
- Rapid cycling: Waterlogged pressure tank or check valve failure
- Air in lines: Water level dropping below pump intake
- Sandy/dirty water: Pump set too deep, screen damage, or failing well
- Tripping breakers: Motor problems, electrical faults, or overheating
- Higher electric bills: Pump working harder due to wear
- No water: Complete pump failure, electrical issue, or dry well
For troubleshooting help, see our guide on signs your well pump is failing.
Submersible Pump Costs
Pump replacement or new installation costs vary based on pump size, well depth, and local labor rates. Here's what to expect in San Diego County:
Pump Prices by Horsepower
| Pump Size | Budget | Mid-Range | Premium |
|---|---|---|---|
| 1/2 HP | $250-$350 | $350-$500 | $500-$700 |
| 3/4 HP | $350-$450 | $450-$650 | $650-$900 |
| 1 HP | $400-$550 | $550-$800 | $800-$1,100 |
| 1.5 HP | $550-$700 | $700-$1,000 | $1,000-$1,400 |
| 2 HP | $650-$850 | $850-$1,200 | $1,200-$1,800 |
Total Replacement Costs
Complete pump replacement including labor typically ranges:
- Shallow wells (under 150 feet): $1,200 - $2,500
- Medium depth (150-300 feet): $2,000 - $3,500
- Deep wells (300-500 feet): $3,000 - $5,500
- Very deep wells (500+ feet): $5,000 - $8,000+
These estimates include pump, drop pipe, wire, fittings, and professional installation. Additional costs may apply for new pressure tanks, control boxes, or well repairs discovered during service.
For detailed pricing, see our well pump replacement cost guide.
Frequently Asked Questions
How long do submersible well pumps last?
Quality submersible well pumps typically last 8-15 years, with premium brands like Grundfos or Franklin Electric often reaching 15-20 years. Lifespan depends on water quality, usage patterns, proper sizing, and installation quality. Pumps in sandy or sediment-heavy wells may have shorter lifespans. Regular maintenance and addressing minor issues promptly helps maximize pump life.
How much does a submersible well pump cost?
Submersible pump costs vary by size and quality. A 1/2 HP pump costs $300-$600, 3/4 HP runs $400-$800, 1 HP costs $500-$1,000, and 1.5-2 HP pumps cost $700-$1,500. Installation typically adds $800-$2,500 depending on well depth. Total replacement cost including pump, installation, and new drop pipe usually ranges from $1,500-$4,500 for residential wells.
What size submersible pump do I need?
Pump sizing depends on well depth, required flow rate (GPM), and total dynamic head. For most homes, a 1/2 HP pump works for wells under 150 feet needing 5-10 GPM. Wells 150-250 feet deep typically need 3/4 HP. Deeper wells or higher water demands require 1-2 HP. Your well's flow rate and your home's peak demand are the key factors. A professional can calculate exact sizing needs.
How do I know if my submersible pump is failing?
Common signs of submersible pump failure include: reduced water pressure, pump running constantly, cycling on/off frequently, air spurting from faucets, dirty or sandy water, higher electric bills, and no water at all. Unusual noises from the well or clicking sounds at the pressure switch also indicate problems. If you notice these symptoms, have your pump inspected promptly to prevent complete failure.
Can I install a submersible pump myself?
While technically possible for shallow wells, DIY submersible pump installation is not recommended. It requires specialized equipment (pulling rig), electrical knowledge, understanding of well systems, and physical capability to handle heavy equipment. Improper installation can damage the pump, contaminate your well, or create safety hazards. In California, electrical connections may require permits. Professional installation ensures proper sizing, safe operation, and typically includes a warranty.
Need Submersible Pump Service in San Diego?
Whether you need pump replacement, troubleshooting, or expert advice on upgrading your well system, our experienced technicians are here to help. We service wells throughout San Diego, Riverside, and San Bernardino Counties with fast response times and competitive pricing.