How to Replace a Sump Pump

It’s important to find a sump pump that has just enough horsepower to handle the water it receives. Choose a pump that can handle normal rainwater and the occasional storm. This depends on the terrain, climate and drainage where you live. Observing how your current pump works can help you pick a new one. 

In general, a 1/3 horsepower submersible pump is fine. Should your home be in a floodplain, you’ll need a stronger sump pump. A sump with a 1/2 horsepower motor is likely enough to handle the extra water. Replace your sump pump if the motor doesn’t have the ideal strength for the water flow on your property.

A motor with high horsepower might run your sump pump too often for your drainage situation. A constantly running pump is prone to burnout. It will wear out faster than it otherwise would. Switch to a smaller motor with less power.

A sump pump that is too weak won’t completely rid the sump pit of water as much or as fast as it needs. It can be more cost effective to buy a smaller pump, but it may not do the job. If the water isn’t pumped out of your basement as quickly as it should, your flood risk is still high. Get a stronger sump pump to prevent basement flooding.

The two main types of sumps are submersible and pedestal. Battery backup sump pumps are excellent during power outages, but they’re generally not primary sump pumps. The pump doing most of the work will likely be a submersible or pedestal sump pump.

Pedestal sump pumps have the motor above the waterline. They’re also known for these characteristics:

• They’re louder than submersible pumps because the motor is out in the open.
• You can add a lid to soften the noise of the water in the pit.
• Cast iron pedestal pumps are more durable than thermoplastic ones.
• Plastic pumps can give you more power for less cost than cast iron, but don’t last as long.
• They can’t handle small debris, like crushed leaves or pebbles, that flows in with the water.

A submersible sump pump has the entire operation underwater. Their advantages include the following:

• They’re quieter than pedestal sumps, especially if they have a lid.
• Submersible pumps support stronger motors and withstand extended short-term use, like severe thunderstorms.
• They’re cooled by the water they sit in, which is useful for processing large volumes of water quickly.
• A cast iron pump will last longer than a plastic one.
• These pumps are strong enough to expel any debris that gets into the sump pit, also known as the water basin.

Battery backup sump pumps are important if your home is prone to power outages during thunderstorms.

• These sump pumps take over the job when your primary pump has no electricity to run.
• They help lessen the strain when your primary pump is struggling to handle a lot of water.
• Battery pumps provide precious time to bail the sump pit if it’s overflowing from an extreme inflow.

To replace a sump pump, take out the existing one first. This is easier when there’s a low water level in the pit:

• Turn off the power at the circuit breaker.
• Unplug the old sump pump and disconnect the discharge line entering it.
• Loosen the pipe clamp on the lower side of the check valve.
• Break the connection around the pipe.
• Remove the pump and the connected short piece of discharge pipe.

Next, center and align your new sump pump:

• Place the pump in the bottom of the sump pit.
• If possible, put the pump on a stone or pump stand so it’s lifted away from the bottom of the pit.
• Assure the new sump pump is level in the pit by checking with a level. If it’s not, use plastic shims to even it out.
• The float should be in the center of the pit, not touching the pump or the sides of the basin. It needs to move freely to function correctly.

If you have a pedestal sump pump, the pump will be in the water, but the motor will be hanging above it. Follow the manufacturer’s instructions for proper installation.

If the old pump and the replacement pumps are an exact match, swap the discharge pipe to the new pump. Make sure there is a check valve for best results with your sump pump.

A check valve in the pipe allows the water to only flow one way. It won’t let water go backwards into your pump when it’s not running. If your new sump pump doesn’t include an integrated check valve, consider adding one. It also improves the sump pump’s lifespan. 

If the old pump and new sump pump are not exactly the same make and model:

• Reuse the old piece of discharge line from the old pump or cut a new piece if needed.
• Insert a male fitting into the discharge opening.
• Screw a discharge pipe into the fitting and fasten the discharge line.
• Assure the arrow on the pipe is pointing up, so the water flow goes up and out of the pit.
• Connect the outlet pipe to the main discharge line, either by tightening a pipe union or by slipping on a rubber fitting and tightening the hose clamps.

Once all the pieces are attached, turn the electricity back on:

• Restore the power at the circuit breaker.
• Plug the cord into a grounded outlet.
• Test the pump by filling the pit with water until the pump is activated. The float should rise with the water, activate the switch and turn on the pump.
• Watch the pump as it processes the water. Make sure it turns off when the water level is below the float.
• If the pump doesn’t turn on even though the float looks activated, cut the power before troubleshooting.

Once your sump pump is working, it’s best to put a lid on the pit. Cover the water basin with a custom sump pit cover that has a cutout for the discharge line and wiring. It helps lessen motor noise for submersible sumps. It also keeps children, pets and bugs out of the sump pit, no matter which pump type you have.