What You Need to Know Before You Start

A submersible well pump sits underwater inside your well casing and pushes water up to your home through a single pipe. Installation means lowering the pump and its attached pipe into the well, connecting it to power and pressure controls at the surface, and testing the system. Most homeowners can handle this work if the well is shallow (under 25 feet) and you have basic plumbing and electrical skills. Deeper wells or wells with existing pump problems often need a licensed well contractor, partly because pulling out a stuck pump or diagnosing casing damage requires specialized equipment.

Before you begin, turn off power to the old pump at the breaker and drain the system by opening a faucet. You will also need to know your well depth, the pump's horsepower rating, and whether your electrical panel has a spare 240-volt circuit (most submersible pumps run on 240 volts). If you are unsure about any of these, call a well contractor for an inspection—a $150 to $300 visit can save you from buying the wrong pump or damaging the well.

Key Takeaways

  • Submersible pumps are lowered into the well on a single pipe and require 240-volt power, so you need a dedicated circuit and a pressure tank at the surface.
  • The pump connects to a check valve, then to the main water line; the electrical cable runs separately up the well casing and connects to a control box.
  • Lowering the pump requires a rope or cable rated for the pump's weight plus water pressure, and the pump must sit on a foot valve or rest on the bottom without touching the casing walls.
  • After installation, you must pressure-test the system and set the pressure switch so the pump turns on and off at the right water levels.
  • If the pump does not prime, water leaks from connections, or the pressure tank does not fill, stop and call a contractor rather than guessing at fixes.

Gather Tools, Materials, and Safety Gear

You will need a submersible pump rated for your well depth (the pump manufacturer prints the maximum depth on the nameplate), a length of Schedule 40 PVC pipe sized to match the pump outlet (usually 1 to 1.5 inches), a check valve, a pressure tank, a pressure switch, a control box or relay, and 240-volt submersible pump cable. You also need two adjustable wrenches, a hacksaw or PVC cutter, PVC primer and cement, Teflon tape, a rope or cable rated for at least twice the pump's weight, and a bucket for catching water during disconnection.

Wear work gloves, safety glasses, and steel-toed boots. Do not work alone—if you fall into the well or get tangled in the rope, you need someone to pull you out or call for help. Keep a fire extinguisher nearby because electrical faults can spark, and never touch the pump cable or connections while the power is on.

Disconnect the Old Pump and Inspect the Well

Turn off power at the breaker and lock it so no one can turn it back on while you work. Open a faucet to drain the system, then disconnect the old pump's electrical cable at the control box by unbolting the wire terminals. Use two wrenches to unscrew the union (the fitting that connects the pump pipe to the main water line) so the old pump and pipe can come out as one piece.

Lower a flashlight on a rope into the well and look for debris, sediment, or cracks in the casing. If you see standing water at the bottom, measure how deep it is—this tells you the static water level and helps you position the new pump. If the casing is cracked or the bottom is full of sand, stop and call a contractor; a damaged well can collapse or contaminate your water.

Once the old pump is out, use a wet/dry vacuum or a submersible utility pump to remove any standing water and sediment from the bottom of the well. The cleaner the well, the longer your new pump will last.

Assemble the Pump, Pipe, and Electrical Cable

Lay the new pump on a clean surface and attach the check valve to the pump outlet using two wrenches and Teflon tape on the threads. The check valve prevents water from flowing backward when the pump stops. Screw the first length of PVC pipe onto the check valve, using PVC primer and cement to seal each joint. Work in sections—glue one 10-foot piece at a time, let it cure for 30 seconds, then add the next piece—until the pipe is long enough to reach from the pump to the surface with 2 to 3 feet extra.

Attach the 240-volt submersible cable to the pump's terminal box by unbolting the cover, inserting the cable through the strain relief fitting, and bolting each wire (usually black, red, and green or bare copper) to its matching terminal. Wrap the cable to the pipe every 3 feet using cable ties or electrical tape so it does not get tangled or pinched. Do not use duct tape; it degrades in water.

At the top of the pipe, attach a sanitary seal or well cap with a hole drilled for the cable. This keeps dirt and insects out of the well while allowing the cable to pass through.

Lower the Pump Into the Well

Tie a rope or cable to the pump's lifting eye (a metal loop on top of the pump housing) and thread it through a pulley or over a beam at the well opening. Never lower the pump by the electrical cable alone—the cable will tear and the pump will fall. Have one person slowly lower the pump while another guides the pipe and cable so they do not twist or snag on the casing edge.

Lower the pump until it rests on the bottom of the well or sits on a foot valve (a one-way valve that sits on the bottom and supports the pump above it). The pump should not touch the casing walls; if it does, it will vibrate and wear through the pipe. Once the pump is in place, remove the rope and find the top of the pipe to the well casing with a clamp so it cannot shift.

Connect the top of the PVC pipe to the main water line using a union and Teflon tape. Tighten by hand first, then use two wrenches to snug it—do not over-tighten or you will crack the fitting. Leave the faucet open so air can escape as the system fills.

Wire the Pump to Power and Install Controls

Run the submersible cable from the well to your electrical panel through conduit (metal or PVC pipe that protects the cable). The cable must connect to a dedicated 240-volt circuit with a 20 or 30-amp breaker (check the pump nameplate for the correct size). If your panel does not have a spare circuit, hire a licensed electrician to add one; running a pump on a shared circuit risks overloading the breaker and starting a fire.

At the well head, connect the cable to a control box or relay that houses the pressure switch and capacitor. The pressure switch turns the pump on when water pressure drops below a set point (usually 30 pounds per square inch) and turns it off when pressure rises to a higher point (usually 50 psi). The capacitor helps the motor start smoothly. If you are not comfortable wiring these components, hire an electrician; mistakes can damage the pump or shock you.

Mount the pressure tank (a steel or composite tank that stores pressurized water and reduces how often the pump cycles) near the control box. Connect it to the main water line with a tee fitting and a check valve so water flows into the tank but not back toward the pump.

Prime, Test, and Adjust the System

Before turning on the power, fill the pressure tank and the main water line with water using a garden hose connected to a neighbor's spigot or a temporary supply. This process, called priming, removes air from the system so the pump does not run dry and overheat. Open the faucet closest to the pump and let water run until it flows steadily with no air bubbles, then close the faucet.

Turn on the breaker and listen for the pump to start. Water should flow from the faucet within 30 seconds. If the pump runs but no water comes out after two minutes, turn it off when ready—the pump is running dry and will burn out. This usually means air is still trapped in the line or the check valve is stuck; stop and call a contractor.

Once water flows, let the pump run until the pressure tank fills and the pressure switch turns the pump off. Watch the pressure gauge on the tank; it should rise to the upper set point (usually 50 psi) and then stop. Open a faucet and watch the pressure drop; the pump should turn back on when pressure falls to the lower set point (usually 30 psi). If the pressure does not rise and fall smoothly, or if the pump cycles on and off every few seconds, the pressure switch or tank may be faulty—turn off the pump and call a contractor.

Common Installation Mistakes to Avoid

Do not use galvanized steel pipe instead of PVC; steel rusts in water and clogs the pump. Do not skip the check valve; without it, water will flow backward and the pump will lose prime every time it stops. Do not run the electrical cable inside the same pipe as the water line; water will eventually damage the insulation and cause a short circuit.

Do not lower the pump too fast or let it swing against the casing; this can crack the pump housing or bend the intake screen. Do not wire the pump to a 120-volt circuit or a shared 240-volt circuit; the pump needs its own dedicated breaker. Do not assume the pressure switch is set correctly; always test it by opening a faucet and watching the gauge to confirm the pump turns on and off at the right pressures.

Do not ignore leaks at the pipe unions or the pressure tank connection; even a small drip will waste water and eventually corrode the fitting. Tighten leaking connections by a quarter turn with two wrenches, then test again. If the leak persists, turn off the pump, drain the system, and replace the fitting.

Frequently Asked Questions

How deep can a submersible pump go?

Most residential submersible pumps are rated for depths between 25 and 300 feet. Check the pump's nameplate for the maximum depth; if your well is deeper than the pump's rating, the pump will not deliver enough pressure and will overheat. A contractor can measure your well depth with a weighted tape or sonic device if you are unsure.

What size pump do I need?

Pump size depends on your household's daily water use and your well's recovery rate (how fast it refills). A typical household uses 75 to 100 gallons per person per day. If your well recovers slowly, you need a larger pressure tank to store water between pump cycles. A well contractor can test your well's flow rate and recommend the right pump size.

Can I install a submersible pump myself if my well is 50 feet deep?

Yes, if you have the right equipment and experience with plumbing and electrical work. A 50-foot well is manageable with a rope and pulley, but you need a pump rated for that depth and a 240-volt circuit. If you are unsure about any step, hire a licensed well contractor; the cost of a professional installation is usually $800 to $1,500 and is worth it to avoid damaging the well or the pump.

What should I do if the pump runs but no water comes out?

Stop the pump when ready. The most common cause is air in the line; re-prime the system by filling the pressure tank and main line with water from an outside source. If priming does not work, the check valve may be stuck or the intake screen may be clogged. Turn off the pump and call a contractor; pulling the pump to clean or replace these parts requires the right equipment.

How often should I service a submersible pump?

Most submersible pumps last 8 to 15 years with minimal maintenance. Have a contractor inspect the pump every 2 to 3 years to check for sediment buildup, corrosion, or electrical faults. If your water is sandy or your well is shallow, the pump may need more frequent cleaning. Keep a record of when the pump was installed and serviced so you know when replacement is likely.