What you need to know before you start

Hooking up a water well pump means connecting the pump itself to the well casing, the pressure tank, and your home's water lines in the right order. The exact steps depend on whether you have a submersible pump (sits inside the well) or a jet pump (sits above ground), but both require the same basic connections: power to the pump, a pipe from the well to the pump, a pipe from the pump to the pressure tank, and a check valve to stop water flowing backward.

This is not a task for someone without plumbing experience if the well is already in the ground. If you are installing a new pump in an existing well, you will almost certainly need a licensed well contractor to pull the old pump out, lower the new one down (submersible pumps can weigh 100 pounds or more), and make sure the electrical connection is safe. If you are building a new well system from scratch or replacing above-ground components, you can do some of the work yourself, but the well itself and the initial pump installation should go to a professional.

Key Takeaways

  • Submersible pumps sit inside the well and require a licensed contractor to install; jet pumps sit above ground and are easier to work with, but both need proper electrical hookup by a licensed electrician.
  • A check valve must go between the pump and the pressure tank to prevent water from flowing backward into the well when the pump stops.
  • The pressure tank stores water under pressure so the pump does not run every time you turn on a faucet, and it connects to the pump outlet with a union fitting for straightforward removal.
  • Pressure switch and relief valve settings control when the pump turns on and off; these are usually set by the installer but should be checked during startup.
  • All electrical connections to the pump must be made by a licensed electrician and protected by a properly sized breaker and ground fault protection.

Submersible pump installation: when to call a professional

A submersible pump sits at the bottom of the well and pushes water up through a single pipe to the surface. Installing one means pulling the old pump out of the well (if there is one), lowering the new pump down the casing on a cable, and connecting it at the top. This requires specialized equipment—a winch or hoist to lower a 100-plus-pound pump safely into a narrow hole without dropping it or damaging the casing—and knowledge of how deep to set the pump so it stays submerged but does not sit on the bottom.

A licensed well contractor has the right tools and knows your local well codes. They will also pull a water sample to check for bacteria before the pump runs, and they will pressure-test the system to make sure there are no leaks. This is not a DIY job. The cost of a contractor call is far less than the cost of a pump stuck at the bottom of a 200-foot well or a contaminated water supply.

Jet pump setup: the above-ground option

A jet pump sits in your basement, garage, or pump house and pulls water up from the well through a suction line. If you are replacing a jet pump or installing one for the first time on an existing well, you have more room to work. The pump itself bolts to a concrete pad or mounting bracket, and the connections are all at ground level.

Start by connecting the suction line—the pipe that runs from the well to the pump's inlet. This line must be airtight; any air leak will cause the pump to lose prime and stop working. Use Schedule 40 PVC or galvanized steel pipe, and seal all threaded connections with plumber's thread seal tape or pipe dope. The suction line should slope slightly downward toward the pump so air pockets do not form. At the well end, the line connects to a foot valve (a one-way valve that keeps water in the line when the pump is off) and a strainer screen to keep debris out.

The discharge line—the pipe leaving the pump—connects to a check valve first. This valve allows water to flow toward the pressure tank but stops it from flowing backward into the pump when the pump shuts off. Without a check valve, water will drain back into the well every time the pump stops, and the pump will have to re-prime itself the next time it starts. After the check valve, the line goes to the pressure tank.

Installing the pressure tank and check valve

The pressure tank stores water under pressure, so the pump does not run every time you open a faucet. A typical residential tank holds 20 to 80 gallons and is connected to the pump outlet with a union fitting—a special connector that lets you disconnect the tank without unthreading the whole line.

The check valve goes between the pump discharge and the pressure tank inlet. Use a swing check valve (the most common type for well systems) or a ball check valve, sized to match your pipe diameter. The valve has an arrow showing the direction water should flow; make sure it points toward the tank. Wrap the threaded connections with thread seal tape and hand-tighten, then use two wrenches—one to hold the valve body and one to turn the fitting—so you do not crack the valve.

Once the check valve is in place, connect the union fitting to the tank inlet. The tank should sit on a level, stable surface and be supported so the weight does not hang on the pipe connections. If the tank is more than a few feet away from the pump, use a larger pipe diameter (1.5 inches instead of 1 inch) to reduce friction and pressure loss.

Pressure switch and relief valve settings

The pressure switch tells the pump when to turn on and off. It is usually mounted on a tee fitting between the pressure tank and the house water line. A typical setting is "cut-in" at 30 pounds per square inch (psi) and "cut-out" at 50 psi—meaning the pump starts when pressure drops to 30 psi and stops when it reaches 50 psi.

The relief valve is a safety device that opens if pressure gets too high, usually set at 10 psi above the cut-out pressure. If your cut-out is 50 psi, the relief valve opens at 60 psi. These settings depend on your water demand, tank size, and local code, so check with your contractor or the pump manufacturer before adjusting them. Most systems come pre-set from the factory.

To check the settings, turn on the pump and watch a pressure gauge (mounted on the tank or the pressure switch) as the tank fills. The pump should stop when the gauge reaches the cut-out pressure. If it does not, the pressure switch may be stuck or out of adjustment. Do not force it; call a well service technician.

Electrical connection and safety

All electrical work on a well pump must be done by a licensed electrician. The pump needs a dedicated circuit with a breaker sized to the pump's amperage rating (found on the pump nameplate), and the circuit must have ground fault protection. For a submersible pump, the electrician will run a waterproof cable down the well casing and connect it to the pump at the bottom; for a jet pump, the cable runs from the breaker panel to the pump motor.

The pump also needs a ground rod driven into the earth near the well or pump house. This protects you if there is a fault in the pump motor. Do not skip this step or use the water line as a ground—it does not work and is dangerous.

Once the electrician has made the connections, do not turn on the pump until the system has been pressure-tested and the pressure switch has been checked. Running a pump with no water in the discharge line will damage it in seconds.

Testing and startup

Before you run the pump for the first time, make sure the pressure tank is pre-charged with air. Most tanks come from the factory with 20 psi of air pressure. Check the air valve on top of the tank with a tire gauge; if it reads zero, the tank may be waterlogged and will not work properly. A waterlogged tank will cause the pump to cycle on and off too often and wear out faster.

Turn on the breaker and listen. The pump should start and run smoothly. Watch the pressure gauge as the tank fills; it should climb steadily to the cut-out pressure, then the pump should stop. Open a faucet and watch the pressure drop; when it reaches the cut-in pressure, the pump should start again. If the pump does not start, or if pressure does not build, turn it off when ready and check for leaks or air in the suction line.

Let the system run for 15 to 20 minutes, then turn off the pump and let it sit for an hour. Check the pressure tank and all connections for leaks. If everything is dry and the pressure gauge is stable, the system is ready to use. If you see leaks or hear unusual noises, turn off the pump and call a well service technician before running it again.

Frequently Asked Questions

Can I install a well pump myself?

You can handle some above-ground connections on a jet pump system, but the pump itself and all electrical work must be done by licensed professionals. Pulling and lowering a submersible pump requires specialized equipment and informed. A mistake can damage the pump, contaminate your water, or create a safety hazard.

What does a check valve do?

A check valve stops water from flowing backward into the well when the pump shuts off. Without one, water drains back down the well, and the pump has to re-prime and work harder the next time it starts. It is a straightforward one-way valve that costs $20 to $50 and lasts for years.

Why does my pump keep turning on and off?

This usually means the pressure tank is waterlogged (full of water instead of air) or the air charge has leaked out. A waterlogged tank cannot store pressure, so the pump runs every time you use water. Check the air valve on top of the tank with a tire gauge; it should read 20 psi or so. If it reads zero, the tank needs to be drained and re-charged or replaced.

How often should a well pump be serviced?

Most well systems should be checked once a year by a licensed technician. They will test water pressure, check the pressure switch and relief valve settings, inspect the tank for corrosion, and make sure all electrical connections are tight. Annual service catches small problems before they become expensive repairs.

What size breaker do I need for my well pump?

The breaker size depends on the pump's full-load amperage, which is printed on the pump nameplate. A licensed electrician will size the breaker correctly and install it. Using the wrong breaker size can damage the pump or create a fire hazard, so do not guess.