Replacing a Well Pump: What You Need to Know

If yours is one of the more than 13 million American households that gets water from a well, your well pump is one of the most crucial pieces of equipment you own. Depending on how deep your well is, the pump may be situated inside your house, in a separate shed near the well, or inside the well itself. Shallow well pumps located outside the well suck water out of the well, while deep well pumps are submerged in the well water and push it to the surface.

Wherever it is, when the pump fails, you've got a major problem, and you'll know it when your water pressure drops or disappears, you have high electric bills, or both. Well pumps last from 10 to 15 years on average, so if you're experiencing well pump problems and you've been in your house long enough to know the pump is near the end of its service life, there's no point trying to fix it. Your plans for the immediate future should include well pump replacement.

This is a job you may be able to DIY and save the cost of a plumber or well service professional, but it really depends on how deep your well is and the type of well pump you have. If you have a very deep well (100 feet deep or more), you have a submersible pump, and no matter how game you are for the job, it may be beyond your ability to pull it out of the well. That's why water well pump repair pros drive around in trucks with winches.

If you have a shallow well, which is one less than 100 feet deep, you probably have a surface-mounted water pump. A well 25 feet deep or less usually has a shallow well jet pump with a single 1 1/4-inch pipe feeding into it from the well. Deeper wells (up to 70 to 100 feet) can have a deep well jet pump, which looks like a shallow well one. In fact, many jet pumps are convertible for use in shallow or deep wells. The difference is that a deep well pump has two pipes feeding into it from the well instead of just one. That's because the jet that creates the suction is located in the well rather than on the pump itself, which allows the pump to create more suction.

Ideally, the replacement pump you purchase should be the same make and model as the existing one because pumps from different manufacturers are configured slightly differently. If you can't find an identical replacement, it's not that big of a deal; it just means you'll probably have to do some extra plumbing to get your existing pipes to fit. The sizes of the intake and output ports are standard, so you won't have to change pipe size. Just make sure your new pump has the same power rating in horsepower as your current one.

If you have a submersible pump and it's not deep enough to make pulling it out of the well by hand an impossible task, you won't know what kind of replacement pump you need until you pull out the existing one. Mitigating against pulling the pump out yourself is the fact that the pump and the water pipe to which it's attached are full of water, which is heavy. Ten feet of 1-inch pipe hold more than 5 gallons weighing over 40 pounds. You may be able to lighten the load by disconnecting the water line and turning on the pump to flush out the water (assuming the pump is still working).

Before you do anything, it's very important to cut power to the pump by turning off the circuit breaker and to shut off the water supply valves coming from the pump and going to the pressure tank or directly to the house. If your system doesn't have a pressure tank, consider installing one to stabilize water pressure in the house. Installation costs vary from $400 to $1,000 depending on the size of the tank.

Once the power is dead, open the pressure switch cover located on the pump and disconnect the wires, open the pressure relief valve on the pump to relieve water pressure, and then open the drain plug to drain the pump. You can now disconnect the pipes to the pump and remove the pump. Set the new pump in place and connect the pipes using whatever extra pipe and fittings are necessary to make them fit. Use plumbing tape on all threaded connections to make a watertight seal.

Before you make the electrical connections, you may have to switch the voltage draw of the pump from 240 to 120 volts depending on your electrical system. Follow the instructions in your owner's manual to do this. Before you turn on the pump, you need to prime it as well as the in-feed pipe. The pipes coming out of the well and out of the pump should have priming plugs. Unscrew them and pour in water until it overflows from the plug openings and then replace the plugs and tighten them down with a wrench. After priming the pump, connect the electrical wires to the pressure switch on the pump and turn on the power to check for leaks.

Deep well jet pumps have two incoming pipes from the well and a single 1-inch pipe to feed water to the pressure tank. The procedure for replacing one differs in three ways from that for replacing a shallow well pump:

• You'll most likely purchase a convertible jet pump (costing $130 to $400), and if you do, you have to remove the impeller from the front of the pump because it goes in the well. Follow the instructions in the owner's manual for doing this.
• You'll have to install a pressure relief valve on the outflow pipe and move the 1/4-inch water tube from the pressure switch, which is affixed to the pump, to that new valve. When you remove the tubing adapter from the pump, you'll have a threaded opening on the pump, and that's a good place to screw in a pressure gauge so you can monitor the water pressure in the pump.
• The impeller that you removed from the pump must be installed on the end of the larger of the two pipes that lead into the well, which means pulling that pipe out of the well. You'll also find a check valve known as a foot valve on the end of that pipe, and it's a good idea to replace that as part of the operation.

Apart from these items, the rest of the procedure is similar to that for a shallow well pump.

A submersible pump sits inside the well casing, and it's connected to a PVC or polybutylene supply pipe and an electrical cable, so don't forget to turn off the circuit breaker before you start. The supply pipe typically feeds into a connector known as a pitless adapter, which connects the well casing to the plumbing system. To extract the pump, you need to screw a length of 1-inch steel pipe into the top of the pitless adapter, which has a sliding connection that separates when you pull on it using the pipe.

The pitless adapter is installed below the frost line, typically from 5 to 10 feet inside the casing, so that's how long your pipe needs to be, and you should add a tee and two lengths of pipe to the top end to make a handle so you can more easily thread the pipe into the adapter. You may need to jolt the adapter apart by tapping upward on the handle of your puller with a hammer, and once it's free, you should be able to pull out the pump, which is usually made of stainless steel to prevent corrosion. Note the make, model, and horsepower and then disconnect the pump and connect the new one. You'll also see a foot valve installed before or after the pump to prevent water from spilling back into the well. You should also replace this valve; you don't want it to fail after you've gone to all the trouble of replacing the pump.

Extracting a submersible pump obviously gets more challenging as the depth of the well increases. If your well is significantly deeper than 100 feet, you'll probably need a winch, so your best bet is to hire a pro to do the job. Professional replacement costs from $1,200 to $1,500 including the cost of the pump, and it's well worth it, especially considering the well service technician will be able to diagnose any other well problems you might be experiencing.

Homeowners may think they need a new well pump when they actually don't because many symptoms that could be caused by a broken pump are often caused by something else in the water system. Sometimes, the actual problem is more serious than a broken well pump, but often, it's something you can easily fix.

• ​No water:​ If water isn't coming from the faucet in the house, the first thing to do is check for a tripped circuit breaker. It's also a good idea to test the pressure switch on the pump because if it's old and the terminals are corroded, it might not be making a good connection. Of course, the well itself may be responsible. If you've had a period of prolonged drought, the water table may have receded. You diagnose this condition by noting dirty water or sediment in the water coming from faucets. If the dirty water comes only when you use a hot water faucet, the culprit is probably the water heater.
• ​Low water pressure:​ A worn-out seal in the water pump motor can cause a loss of water pressure but so can a leak in the system — which you should be able to spot fairly easily — or a waterlogged pressure tank. The pressure tank has an air valve on the top, and if water comes out when you depress it, your pressure tank — and not the pump — needs to be replaced.
• ​Low water level in the storage tank:​ Some deep well systems include a nonpressurized storage tank into which the well pump deposits water, and these systems usually have an auxiliary pressure pump to charge the pressure tank. If the water level in the storage tank is always low, the pump may be wearing out, but the float in the tank may also be malfunctioning. Manually move the float around and if there's no water flow, you probably need to replace the float.
• ​Air bubbles in the water:​ If your water well pump has a bad seal, it can allow air into the water, but air bubbles may also signify a leak in the water line. They could also be coming from the pressure tank because if the bladder is ruptured, it allows the air in the upper part of the tank to mix with the water in the lower part.