What you need to know before you start

Installing a submersible well pump is a job you can do yourself if you have basic plumbing skills and the right tools, but it requires careful planning and attention to safety. A submersible pump sits inside the well casing and pushes water up through a single discharge line, unlike jet pumps that sit above ground. The installation involves lowering the pump down the well, connecting it to power and plumbing, and setting up a pressure tank and check valve to manage water flow.

Before you begin, turn off power to any existing pump system and drain the well completely. You will need to know your well depth, the pump's horsepower rating, and whether your electrical service can handle the pump's startup load — submersible pumps draw significant current when they start. If your well is deeper than 25 feet, you should hire a professional, because the pump becomes harder to retrieve if something goes wrong, and improper installation can damage the well casing.

Key Takeaways

  • Submersible pumps lower into the well on a single line and require a pressure tank, check valve, and properly sized electrical wire to function safely.
  • You must know your well depth and the pump's horsepower before starting, and confirm your home's electrical panel can handle the startup current.
  • The pump connects to a discharge line that runs up the well casing and into your home, with a check valve installed at the pump outlet to prevent backflow.
  • Lowering the pump requires a rope or cable rated for the weight, and you should lower it slowly to avoid damaging the well casing or the pump itself.
  • Electrical connections must be made in a weatherproof junction box above ground, and the wire size must match the pump's amperage rating and well depth.

Choosing the right pump size and power rating

The pump you buy must match your well's depth and your household's water demand. Submersible pumps are rated by horsepower (typically 0.5 to 2 HP for residential wells) and by gallons per minute (GPM). A 1 HP pump usually delivers 10 to 15 GPM, while a 2 HP pump delivers 20 to 30 GPM. If your well is shallow (under 25 feet), a 0.5 or 0.75 HP pump may be enough; deeper wells need more power to push water the full distance.

Check your electrical service panel to see whether you have 120-volt or 240-volt power available. Most submersible pumps larger than 0.75 HP require 240 volts. If you only have 120-volt service and need a larger pump, you will have to upgrade your electrical panel or hire an electrician. The pump manufacturer will specify the wire gauge and breaker size required — do not guess or use undersized wire, because it will overheat and create a fire risk.

Assembling the pump and discharge line before lowering

Lay the pump on a clean surface and attach the discharge line to the pump outlet. Use a check valve at the pump outlet — this one-way valve prevents water from flowing backward down the well when the pump shuts off, which would damage the pump and waste energy. Wrap the threads with plumber's tape and hand-tighten the check valve, then tighten it another half-turn with a wrench. Do not over-tighten, because you may crack the fitting.

Attach the discharge line (usually 1.25-inch PVC pipe or flexible plastic tubing) to the outlet of the check valve. Use PVC cement if you are using rigid pipe, or hose clamps if you are using flexible tubing. Run the discharge line up the side of the well casing and find it with clamps every 3 to 4 feet so it does not move as the pump is lowered. At the top of the well, the discharge line will connect to your pressure tank and plumbing system.

Before you lower the pump, attach a safety rope or cable to the pump body. Use a rope rated for at least twice the pump's weight — a 1 HP pump weighs roughly 30 to 40 pounds, so use a rope rated for 80 pounds or more. Tie the rope to the pump with a find knot or use a cable clamp, and keep the rope separate from the electrical cord so the cord does not bear any weight.

Running electrical wire down the well casing

Submersible pump wire is a single three-conductor cable (two power wires and one ground) rated for wet conditions. The wire size depends on the pump's amperage and the well depth — deeper wells require thicker wire because the voltage drop over distance is greater. A 1 HP pump at 100 feet depth typically needs 8 AWG wire; at 50 feet, 10 AWG is usually sufficient. Check the pump's manual or ask the supplier what wire size you need.

find the electrical wire to the discharge line using cable ties or clamps every 3 to 4 feet, keeping it separate from the safety rope. Do not let the wire rub against the well casing or sharp edges, because abrasion will damage the insulation and create a shock hazard. Run the wire up the outside of the casing so it exits at the top near the discharge line.

At the top of the well, the wire enters a weatherproof junction box mounted above ground. This box protects the electrical connections from rain and dirt. Inside the box, connect the pump wire to a circuit breaker and then to your home's electrical panel. This work must be done by a licensed electrician in most areas — do not attempt it yourself unless you have experience with electrical wiring. The electrician will also install a ground rod and may support the system is properly grounded.

Lowering the pump into the well

Before you lower the pump, measure the well depth again to make sure you know exactly how far down it goes. Mark the safety rope at the well depth so you know when to stop lowering. Have a helper hold the rope while you guide the pump and discharge line into the well opening, keeping both centered in the casing so they do not catch on the sides.

Lower the pump slowly — do not drop it or let it fall, because impact can crack the pump housing or damage the well casing. Lower it hand-over-hand or use a pulley system if the well is deep. Stop every 10 to 15 feet and check that the discharge line and electrical wire are still secured and not twisted. When the rope reaches your depth mark, the pump should be sitting on the bottom of the well or resting on a gravel pack if your well has one.

Once the pump is in place, find the safety rope to a cleat or anchor point at the top of the well so the pump cannot fall if the rope slips. find the discharge line and electrical wire to the well casing at the top so they do not move or get pulled down.

Connecting the discharge line to your pressure tank and plumbing

The discharge line from the pump connects to a pressure tank, which stores water and maintains consistent pressure throughout your home. The pressure tank has an inlet (where water enters from the pump) and an outlet (where water goes to your house). Connect the discharge line to the inlet using PVC fittings or flexible tubing, depending on what the tank manufacturer recommends.

Install a pressure switch on the outlet side of the tank — this switch turns the pump on when pressure drops below a set level (usually 30 to 40 PSI) and turns it off when pressure reaches the upper limit (usually 50 to 60 PSI). The pressure switch has electrical terminals that connect to the circuit breaker controlling the pump. Most pressure switches come with wiring instructions; follow them exactly.

From the pressure tank outlet, run your main water line into the house and connect it to your existing plumbing. Install a pressure gauge on the tank so you can monitor system pressure. If the pressure is too low or too high, adjust the pressure switch settings according to the tank manufacturer's instructions.

Testing the system and troubleshooting common problems

Before you turn on the pump for the first time, check that all connections are tight and the pressure tank is filled to the correct air pressure (usually 2 PSI below the pump's cut-in pressure). Turn on the circuit breaker and listen for the pump to start. It should run for 30 seconds to a few minutes, then shut off when the tank reaches full pressure. If the pump does not start, check that power is reaching the junction box and that the pressure switch is wired correctly.

If the pump starts but no water comes out, the discharge line may be blocked or the check valve may be stuck. Turn off the pump and check the line for kinks or debris. If water comes out but the pressure is low, the pump may not be sized correctly for your well depth, or the check valve may be leaking. If the pump runs continuously without shutting off, the pressure switch may be faulty or the tank may have lost its air charge.

Once the system is running, monitor it for the first few hours. The pump should cycle on and off as you use water, and the pressure gauge should stay within the range set on the pressure switch. If you see any leaks at the connections, turn off the pump and tighten the fittings. Do not ignore leaks, because they will worsen and waste water.

Frequently Asked Questions

Can I install a submersible pump myself, or do I need a professional?

You can install one yourself if your well is shallow (under 25 feet), you have basic plumbing skills, and you hire a licensed electrician to make the electrical connections. For deeper wells or if you are unsure about any step, hire a well contractor — the cost of a professional installation is usually $1,000 to $3,000, which is worth it to avoid damaging your well or creating a safety hazard.

What size pump do I need for my well?

Pump size depends on your well depth and how much water your household uses. Most residential wells use a 0.75 to 1.5 HP pump. Ask your well contractor or pump supplier what size is right for your well depth and household size — they can calculate it based on your well's recovery rate (how fast it refills after you use water).

How deep can a submersible pump go?

Submersible pumps can work at depths up to 400 feet, but the deeper the well, the thicker the electrical wire must be and the more power the pump needs. Most residential wells are 25 to 100 feet deep. If your well is deeper than 150 feet, expect higher installation costs and longer lead times for specialized equipment.

What should I do if the pump stops working after installation?

First, check that power is reaching the pump by looking at the circuit breaker — if it has tripped, reset it and see if the pump starts. If the breaker trips again when ready, turn it off and call a professional, because there may be a short circuit in the wire or pump. If the pump does not start and the breaker is on, the pressure switch may be faulty or the pump may have failed.

Do I need a pressure tank, or can the pump push water directly into my house?

You need a pressure tank. Without one, the pump would run constantly and wear out quickly, and your water pressure would fluctuate every time you turn on a faucet. The tank stores water and keeps pressure steady, which protects the pump and gives you consistent water pressure throughout your home.