What happens when you replace a submersible well pump

Replacing a submersible well pump means pulling the old pump out of the well, disconnecting it from the electrical and water lines, lowering a new pump down into the well on a new drop pipe, and reconnecting everything. The pump sits at the bottom of the well casing, so the job requires either a winch or a hand-crank pulley system to haul the old one up—usually 50 to 400 feet depending on your well depth. Most homeowners hire a licensed well contractor for this work because it involves electrical connections, pressure tank adjustments, and the risk of damaging the well casing if something goes wrong.

The entire process typically takes four to eight hours. You will have no water during that time, so plan accordingly. If you decide to do it yourself, you need to understand the electrical disconnect, the mechanics of lowering pipe safely, and how to prime the system afterward. Many people choose to hire out because the cost of a mistake—a broken well casing or a pump stuck halfway down—far exceeds the contractor fee.

Key Takeaways

  • A submersible pump sits at the bottom of your well and must be pulled up entirely to be replaced, which requires specialized equipment and takes most of a day.
  • You will need to shut off power at the breaker, disconnect the drop pipe and electrical cable, and have a way to lift the old pump out safely.
  • The new pump must be lowered carefully on new drop pipe, and the system must be primed and pressure-tested before water returns to your house.
  • Most homeowners hire a licensed well contractor because the electrical work and depth of the well make this a job where mistakes are costly.
  • Pump replacement costs vary widely by well depth, pump size, and your region, but a contractor visit typically runs between $1,500 and $5,000 total.

Signs your submersible pump needs replacement

A submersible pump usually fails suddenly rather than gradually. Common signs include no water at all, water that comes out in spurts or with air in it, a humming sound from the pressure tank but no water flowing, or a breaker that trips repeatedly when you try to run water. If the pump is more than 15 to 20 years old and has stopped working, replacement is almost always cheaper than repair.

Sometimes the problem is not the pump itself but a tripped breaker, a frozen pipe, or a pressure tank issue. Before you assume the pump is dead, check that the breaker is on, listen for any sound from the pump (a faint hum means power is reaching it), and look for visible leaks or ice around the well cap. If the pump is humming but no water comes out, the pump may be running dry because the well has run dry, or the check valve is stuck. These are different problems from pump failure and may have cheaper fixes.

Turning off power and disconnecting the old pump

Start by switching off the breaker that controls the pump. The breaker is usually labeled "well pump" or "submersible pump" in your electrical panel. Leave it off for at least five minutes to may support all power has drained. Then go to the well head and look for the electrical cable coming out of the ground—this is usually a thick, weatherproof cable running to a junction box or directly to the house. Do not touch this cable while the breaker is on.

Next, you need to disconnect the drop pipe, which is the rigid pipe that runs down into the well carrying water up to the house. This pipe is usually connected to a fitting at the top of the well casing with a union (a threaded connector that unscrews). Use two pipe wrenches—one to hold the fitting still and one to turn the union—and turn slowly because there is water pressure in the pipe. Have a bucket ready because water will spill. Once the pipe is loose, you can cap it or plug it to keep debris out of the well.

The electrical cable is usually connected to the pump with a waterproof connector at the top of the well or inside a junction box. This connector may be a threaded cap, a compression fitting, or a splice wrapped in waterproof tape. If you are not certain how to disconnect it safely, stop here and call a contractor. Damaging the electrical connection or leaving it exposed to water can create a shock hazard.

Pulling the pump out and preparing the well

Once power and water lines are disconnected, you need a way to pull the pump up. If you have a winch on a truck or a portable electric winch, you can rig it to a tripod over the well. If you do not have a winch, a hand-crank pulley system (sometimes called a come-along or a block and tackle) works for shallow wells under 100 feet, but it is slow and tiring. For deep wells, a winch is nearly essential.

Attach a cable or rope to the pump's lifting eye (a metal loop at the top of the pump casing) and begin pulling slowly and steadily. The pump will be heavy—anywhere from 50 to 200 pounds depending on size—and the drop pipe adds weight as it comes up. Pull straight up; if the pump tilts or binds, stop and adjust the angle before continuing. As the pump rises, coil the drop pipe on the ground in a safe place where it will not kink or get stepped on.

Once the pump is out, inspect the well casing for cracks or damage. Look down into the well with a flashlight if you can. If you see cracks, sediment, or rust, the well itself may need work before a new pump goes in. This is another reason to hire a contractor—they can assess the well condition and advise whether it is safe to proceed.

Installing the new pump and drop pipe

Before lowering the new pump, check that it matches your old pump's voltage and horsepower. The nameplate on the pump will show these details. You will also need new drop pipe cut to the exact length of your well—measure from the top of the casing to the depth where the pump will sit (usually a few feet above the bottom to avoid sucking up sediment). The pipe is usually 1.25 inches or 1.5 inches in diameter and comes in sections that screw together.

Assemble the drop pipe on the ground, then attach it to the pump's inlet fitting using two wrenches to keep the connection tight. Lower the pump and pipe slowly into the well, feeding the pipe down as the pump descends. This is where a winch is invaluable—you can control the speed and stop if something binds. Hand-lowering is possible but risky because the weight can slip and drop the pump.

Lower the pump until it sits at the correct depth, usually 10 to 20 feet above the bottom of the well. Once it is in place, connect the drop pipe to the fitting at the top of the well casing using a union, hand-tightening first and then using two wrenches to snug it. Do not over-tighten; you will need to disconnect it again someday.

Reconnecting power and priming the system

The electrical cable must be reconnected to the pump's terminal box. If the old cable is still good and long enough, you can reuse it; otherwise, you will need new submersible pump cable rated for the depth of your well. The cable connects to the pump with a waterproof connector—usually a compression fitting or a threaded cap. Wrap the connection in waterproof tape or use a waterproof junction box to protect it from moisture.

Before you turn the breaker back on, you need to prime the system. Priming means filling the drop pipe with water so the pump does not run dry when it starts. Open the priming valve (a small valve near the top of the well head or on the pressure tank) and pour water down it until water comes out the other side, then close the valve. Some systems have a priming plug instead—remove it, fill the pipe, and replace the plug.

Now switch the breaker back on. The pump should start and begin pushing water up into the pressure tank. Listen for the pump to run smoothly without grinding or squealing. Watch the pressure gauge on the tank—it should rise from zero to your system's cut-in pressure (usually 30 to 40 pounds per square inch). Once pressure reaches the cut-in point, the pump should shut off. If it does not shut off, or if it cycles on and off rapidly, there may be an air leak or a problem with the pressure tank.

Testing water flow and checking for leaks

Once the pump has run and pressure is stable, open a faucet slowly and let water run for a minute. The water may be cloudy or discolored at first because air and sediment are being pushed out of the system. Let it run until it clears. Check all visible connections—the union at the top of the well, the pressure tank inlet, and any fittings in the house—for drips or sprays. Tighten any connection that leaks, using two wrenches to avoid stripping the fitting.

Run water at several faucets and observe the pressure. It should stay steady and not drop suddenly. If pressure drops when you open a faucet and does not recover, there may be an air leak in the drop pipe or a problem with the check valve. If water comes out with a lot of air or sputters, the pump may not be fully primed or the well may be running low. Let the system run for 15 to 20 minutes and check again; sometimes air takes time to work out.

When to call a professional well contractor

Hire a contractor if you do not have a winch or safe way to pull the pump, if you are unsure about the electrical connections, if the well is deeper than 150 feet, or if you notice cracks or damage to the well casing. A contractor has the equipment, insurance, and experience to do the job safely and to diagnose well problems you might miss. They can also pull a water sample to test for contamination, which is good practice after any work on a well.

Contractor costs vary by region and well depth. A shallow well (under 100 feet) with a standard pump replacement might cost $1,500 to $2,500. A deep well (200+ feet) or a pump that is stuck or corroded can run $3,000 to $5,000 or more. Get quotes from at least two contractors and ask what is included—some include pressure tank inspection and priming, others charge extra for those services. Ask whether they will test the water after installation and whether they offer a warranty on the pump.

Frequently Asked Questions

How long does a submersible pump usually last?

Most submersible pumps last 8 to 15 years with normal use. Factors that shorten life include running dry, high sediment in the well, power surges, and continuous cycling because of a leaky pressure tank. Pumps in areas with hard water or high iron content may fail sooner because mineral buildup clogs the impeller.

Can I replace just the pump and reuse the old drop pipe?

Reusing old drop pipe is risky. The pipe may have corrosion inside that will clog the new pump, or it may have cracks that let sediment in. Most contractors recommend new pipe with a new pump. Old pipe is inexpensive compared to the cost of a pump failure, so replacement is usually the safer choice.

What if the pump gets stuck and will not come up?

A stuck pump usually means corrosion has bonded it to the casing or the drop pipe is bent. Do not force it—you can break the casing or the pump. Stop pulling, wait a day or two, and try again; sometimes the pump will loosen. If it stays stuck, call a contractor with heavier equipment. They may be able to work it loose or, in rare cases, may need to abandon the well and drill a new one.

Do I need a permit to replace my well pump?

Permit requirements vary by county and state. Some areas require a permit for any well work; others only for new wells or major repairs. Contact your county health department or building department before you start. A contractor will usually handle permits as part of their service.

What should I do if water comes out cloudy after pump replacement?

Cloudy water after replacement is usually air or fine sediment being pushed out of the system. Run water at a faucet for 5 to 10 minutes and it should clear. If it stays cloudy for more than an hour, the well may have high sediment or the pump may be stirring up the bottom. Let the system sit for a few hours and try again. If cloudiness persists, have the water tested.