When and why to remodel your sump pump

A sump pump remodel means replacing the pump itself, upgrading the discharge line, or both. You need to do this when your current pump fails to keep water out during heavy rain, when it runs constantly without lowering the water level, or when it has reached the end of its typical lifespan — usually 7 to 10 years for a submersible pump, 5 to 7 years for a pedestal model.

The most common reason to remodel is that the pump motor burns out or the impeller clogs with sediment. A second reason is that your basement floods despite the pump running, which usually means the pump is undersized for your water volume or the discharge line is blocked or too long. A third reason is that you want to add a backup pump or switch from a single pump to a system with both primary and battery-powered backup.

Remodeling is not the same as repair. If your pump is still running but slower, or if it cycles on and off more often than it used to, a technician can sometimes clean the intake screen or unclog the discharge line. But if the motor no longer starts, or if it runs but produces no water, replacement is usually the only option.

Key Takeaways

  • Submersible pumps last 7 to 10 years and pedestal pumps last 5 to 7 years; replacement becomes necessary when the motor fails or the pump cannot keep up with water volume.
  • You will need to know your basin size, the depth of water that collects, and how far the discharge line must travel to choose a pump with the right horsepower and flow rate.
  • Replacing a pump yourself requires draining the basin, disconnecting the old pump, installing the new one, and testing it before closing the pit — a task that takes 2 to 4 hours for a submersible pump.
  • Discharge line upgrades often prevent future failures; moving from a kinked or undersized line to a straight, properly sloped line can stop flooding even without changing the pump.
  • A backup pump or battery-powered system costs more upfront but prevents basement flooding if the primary pump fails during a storm.

Measure your basin and water volume before buying

The pump you choose must match the amount of water your sump pit collects. Start by measuring the pit itself: width, length, and depth. Then run water into it from a hose and time how long it takes to fill to the level where your current pump turns on. This tells you the gallons per minute (GPM) your pump must handle.

Most residential sump pits are 18 to 24 inches across and 24 to 36 inches deep. If water fills a 2-foot-by-2-foot-by-2-foot pit in 5 minutes, your pump needs to move at least 32 gallons per minute. If it fills in 2 minutes, you need 80 GPM or more. Write down this number — it is the minimum flow rate for your replacement pump.

Also measure how far the discharge line must travel from the pit to the outside of your house. If it is more than 50 feet, or if it must go uphill, you need a pump with higher horsepower to push water that distance. A 1/3 horsepower pump works for most basements with short, downhill discharge lines. A 1/2 horsepower pump is needed for longer runs or higher lift.

Choose between submersible and pedestal pumps

A submersible pump sits inside the sump pit, under water. It is quieter, takes up no floor space, and lasts 7 to 10 years. The downside is that it is harder to inspect and repair, and when it fails, you must drain the pit to remove it. Most homeowners choose submersible pumps for finished basements where noise matters.

A pedestal pump stands on a column above the pit, with an intake pipe reaching down into the water. It is easier to service and lasts 5 to 7 years. The downside is that it is louder and takes up floor space. Pedestal pumps are common in unfinished basements and crawl spaces where noise is not a concern and space is tight.

For a remodel, stay with the type you have unless you have a specific reason to switch. If you are replacing a submersible pump with a submersible, the pit and discharge line are already sized for that type. If you want to switch from pedestal to submersible, you may need to enlarge the pit slightly to fit the wider pump housing.

Disconnect the old pump and prepare the pit

Turn off power to the pump at the circuit breaker. Unplug the pump cord from the outlet if it is a plug-in model. If the pump is hardwired, turn off the breaker and leave it off until the new pump is installed.

For a submersible pump, you will need to drain the pit first. Use a wet-dry vacuum or a submersible pump to remove the water, or bail it out by hand if the pit is small. Once the pit is empty, disconnect the discharge line from the pump outlet. This is usually a threaded fitting or a hose clamp. Loosen the fitting with a wrench and set the line aside.

Lift the old pump out of the pit. If it is heavy or stuck, rock it gently side to side. Once it is out, inspect the pit for sediment, debris, or cracks. Scoop out any sediment that has accumulated at the bottom. If you see cracks in the pit walls, you may need to seal them or replace the pit before installing the new pump.

Install the new pump and reconnect the discharge line

Lower the new pump into the pit. For a submersible pump, make sure the intake screen at the bottom is clear and facing downward. Position the pump so the outlet fitting points toward where the discharge line will connect. If the pit has a check valve installed on the old pump, remove it and install it on the new pump in the same orientation — the arrow should point away from the pump.

Connect the discharge line to the pump outlet. If you are reusing the old line, inspect it first for cracks, kinks, or blockages. A kinked or undersized line is often the reason the old pump failed. If the line is damaged or undersized, replace it with new PVC or flexible discharge tubing one size larger. Most residential pumps use 1.5-inch or 2-inch discharge lines.

Make sure the discharge line slopes downward as it leaves the pit and the house. A slope of at least 1/8 inch per foot prevents water from backing up into the pit when the pump stops. If the line must go uphill at any point, add a check valve at that point to prevent backflow.

Test the pump before closing the pit

Fill the pit with water from a hose until the water level reaches the float switch or pressure switch that turns the pump on. The pump should start automatically. Watch it run for 2 to 3 minutes and confirm that water is flowing out the discharge line and away from the house. If water is not flowing, the discharge line may be blocked or the pump may not be seated correctly in the pit.

Once the pump is running, let it run until the water level drops below the switch and the pump stops. This confirms that the pump can turn off and that the float or pressure switch is working. If the pump does not stop, the switch may be stuck or installed incorrectly.

Run the test cycle two or three times. Each time, the pump should start when the water reaches the switch level and stop when the water drops below it. If the pump runs continuously or does not start at all, turn off the power and troubleshoot before closing the pit.

Upgrade the discharge line if the old one is failing

The discharge line is often the weak point in a sump pump system. A line that is too small, too long, or kinked will reduce the pump's flow rate and cause the pit to overflow during heavy rain. If your old pump was failing, the line may be the reason.

Replace the line with PVC pipe or flexible discharge hose one size larger than the old line. Use a straight path from the pit to the outside of the house whenever possible. Avoid sharp bends and loops. If the line must turn, use a long-radius elbow rather than a sharp 90-degree elbow.

The discharge outlet should be at least 4 to 6 feet away from the foundation and should slope downward so water runs away from the house. If the outlet is close to the foundation or if water pools near the house, extend the line or add a splash block to direct water farther away.

Consider a backup pump or battery system

A backup pump is a second, smaller pump that turns on if the primary pump fails or cannot keep up with water volume. It is wired to a separate circuit and float switch so it operates independently. A backup pump costs $300 to $600 and takes 2 to 3 hours to install, but it prevents basement flooding if the primary pump motor burns out during a storm.

A battery-powered backup system uses a sealed battery and inverter to power a small pump when the main power fails. These systems cost $800 to $1,500 and can run for 6 to 12 hours depending on water volume. They are useful if your area has frequent power outages or if you want maximum protection.

For most homeowners, a backup pump is the better choice because it uses the same power source as the primary pump and does not require battery maintenance. A battery system is worth the extra cost only if you live in an area with frequent storms and power outages.

Frequently Asked Questions

Can I replace a sump pump myself or do I need a plumber?

You can replace a submersible pump yourself if you are comfortable draining the pit, disconnecting fittings, and testing the new pump. The work takes 2 to 4 hours and requires basic tools: a wrench, a wet-dry vacuum, and a hose. If you are unsure about any step, hire a plumber — the cost is usually $400 to $800 for labor and pump.

How much does a new sump pump cost?

A submersible pump costs $150 to $400 depending on horsepower and brand. A pedestal pump costs $100 to $300. Installation labor is $400 to $800 if you hire a plumber. Upgrading the discharge line adds $200 to $500. A backup pump system adds $300 to $1,500.

What size pump do I need?

Most residential basements need a 1/3 horsepower pump with 40 to 60 GPM flow rate. If your pit fills faster than 5 minutes or if the discharge line is longer than 50 feet, you need a 1/2 horsepower pump with 60 to 80 GPM. Measure your pit size and fill rate to be sure.

Should I replace the discharge line when I replace the pump?

Inspect the old line first. If it is kinked, cracked, or undersized, replace it. A new line costs $200 to $500 and often solves flooding problems that the pump alone cannot fix. If the old line is straight and in good condition, you can reuse it.

How often do sump pumps need to be replaced?

Submersible pumps last 7 to 10 years with normal use. Pedestal pumps last 5 to 7 years. If your pump runs constantly or cycles on and off more than once per hour during dry weather, it may be failing and should be replaced soon.