What you need to know before you start

Replacing a submersible well pump is a job you can do yourself if you have basic mechanical skills and the right tools, but it requires careful planning because the pump sits at the bottom of your well — sometimes 100 feet down or more. The work involves pulling the old pump and pressure tank out of the ground, disconnecting electrical and water lines, lowering a new pump into the well on a new drop pipe, and reconnecting everything. Most homeowners either hire a well contractor (typically $1,500 to $3,000 for labor and parts) or rent a pump puller and do the heavy lifting themselves.

The first step is knowing what pump you have. Look at the nameplate on your current pump or pressure tank — it will show the horsepower, voltage, and depth rating. You need this information to order the correct replacement. If you cannot find the nameplate, measure the diameter of the pump (usually 3 or 4 inches) and note the well depth from your well log or the original drilling paperwork. Take photos of how the old pump is wired before you disconnect anything.

Key Takeaways

  • You will need to pull the pump and drop pipe out of the well, which requires either renting a pump puller or hiring a contractor — this is the hardest part of the job.
  • Turn off power at the breaker and drain the pressure tank completely before you start any work.
  • The new pump must match the old one's horsepower, voltage, and diameter, or it will not fit in the well casing.
  • Drop pipe, foot valve, and check valve often need replacement at the same time as the pump because they wear out together.
  • Lowering the pump back into the well and reconnecting wiring must be done carefully to avoid damaging the pump or getting water into the electrical connections.

Turning off power and draining the system

Before you touch anything, switch off the breaker that controls the pump at your electrical panel. If you are not certain which breaker it is, turn it off and have someone turn on a faucet — the water should stop flowing. Leave the breaker off for the entire job.

Next, drain the pressure tank. Open the drain valve at the bottom of the tank and let all the water run out into a bucket or onto the ground. This step is critical because a pressurized tank can spray water and cause injury when you disconnect the lines. After the tank is empty, open a faucet in the house to release any remaining pressure in the pipes. You should hear air hiss out.

Pulling the pump and drop pipe from the well

This is the most physically demanding part. The pump sits at the bottom of the well attached to a long pipe (the drop pipe) that runs from the pump to the surface. You have to pull both out together. If the well is shallow (under 30 feet), you may be able to do this with a rope and a hand winch or come-along attached to a sturdy frame above the well. For deeper wells, rent a pump puller from a tool rental shop — it is a tripod with a motorized winch that costs $50 to $100 per day.

Before you start pulling, disconnect the electrical wires from the pump. Take a photo of the wire connections first. Unbolt the drop pipe from the well head (the fitting at the top of the well casing). Then attach your pulling equipment to the drop pipe and begin raising it slowly. As the pipe comes up, have someone guide it and stack it on the ground in manageable sections — do not let it fall or kink. Once the pump is out, set it aside.

Inspecting and replacing the drop pipe and foot valve

While the pump is out, inspect the drop pipe for cracks, corrosion, or mineral buildup. If the pipe is more than 20 years old or shows significant damage, replace it. The foot valve (a one-way check valve at the bottom of the drop pipe) almost always needs replacement because it wears out at the same rate as the pump. A new foot valve costs $30 to $60.

Unscrew the old foot valve from the bottom of the drop pipe using two pipe wrenches — one to hold the pipe and one to turn the valve. Wrap the threads of the new foot valve with plumber's thread seal tape (wrap it clockwise, three to four times around) and screw it on hand-tight, then use a wrench to snug it another quarter turn. Do not over-tighten or you will crack the valve.

If you are keeping the old drop pipe, clean off any mineral deposits with a wire brush. If you are installing new pipe, measure the well depth and have the pipe cut to length at the supplier — it should reach from the bottom of the well to about 2 feet above the well head so you have room to work.

Installing the new pump on the drop pipe

Lay the new pump on a clean surface and attach the drop pipe to the pump inlet (the opening at the bottom). Use two pipe wrenches again — one to hold the pump and one to turn the pipe connection. Wrap the threads with plumber's thread seal tape first. Tighten firmly but do not force it; the connection should be snug, not strained.

Once the pump is attached to the drop pipe, you are ready to lower it back into the well. This requires two people: one to guide the pipe down the well casing and one to operate the winch or come-along. Lower the assembly slowly and steadily. Stop every 10 to 15 feet and check that the pipe is going straight down and not binding against the sides of the casing. If it binds, raise it slightly, straighten it, and try again. Lowering a 100-foot well takes 20 to 30 minutes if done carefully.

Reconnecting the drop pipe and electrical wiring

Once the pump is at the bottom of the well, bolt the drop pipe to the well head fitting at the top. Use the bolts and clamps that came with your pump or well head — typically two or three bolts that you tighten in a cross pattern (like tightening a car wheel) to keep the pipe centered.

Now reconnect the electrical wires. Match the wire colors to the photo you took earlier — usually black to black, white to white, and green or bare copper to ground. If the wires are corroded or damaged, cut off the damaged section and strip about half an inch of insulation from each wire. Twist the matching wires together and cover the connection with a waterproof wire connector rated for outdoor use (not a regular wire nut). Wrap the entire connection with waterproof electrical tape. If you are not confident with electrical work, hire a licensed electrician for this step.

Reconnecting the pressure tank and testing the system

Reconnect the water line from the well head to the pressure tank using the same fittings that were there before. If the old fittings are corroded or leaking, replace them with new brass fittings and wrap the threads with plumber's thread seal tape. Tighten by hand first, then use a wrench to snug each fitting another quarter turn.

Close the drain valve on the pressure tank. Turn the breaker back on at the electrical panel. The pump should start automatically and begin filling the pressure tank. Listen for the pump to run and watch for water flowing into the tank. The pump will run until the pressure inside the tank reaches the cut-off point (usually 60 pounds per square inch), then it will stop. This first fill may take 10 to 15 minutes. Once the pump stops, open a faucet in the house and let water run for a minute to check that the system is working and there are no leaks at the connections.

Frequently Asked Questions

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

You can, but the drop pipe and foot valve wear out at the same rate as the pump. If your pump is being replaced because it failed, the foot valve is likely failing too. Replacing both at once costs more upfront but saves you from pulling the pump again in a few years. If the drop pipe is less than 10 years old and shows no corrosion, it is usually safe to reuse.

What if I cannot pull the pump myself?

Hire a licensed well contractor. They have the equipment and experience to pull the pump safely without damaging the well casing. The cost is higher than renting a pump puller, but you avoid the risk of getting stuck halfway through the job. Get quotes from at least two contractors before you decide.

How do I know if my pump is actually bad?

Common signs are low water pressure, the pump running constantly without building pressure, or the breaker tripping repeatedly. If the pump is running but no water is coming out, the foot valve may be stuck — try turning the power off and on a few times to see if it clears. If that does not work, the pump or foot valve needs replacement.

Do I need a permit to replace my own pump?

Requirements vary by county. Some counties require a licensed contractor to do the work; others allow homeowners to do it themselves but require a permit and inspection. Call your county health department or building department before you start to find out what applies where you live.

What size pump do I need?

The new pump must match the old one in horsepower, voltage, and diameter. If you cannot find the nameplate on your old pump, contact the well contractor who installed it or the pump manufacturer with your well depth and current water usage. They can recommend the right size. Oversizing the pump wastes electricity; undersizing it will not meet your household demand.