What You Need to Do Before You Start
Installing a sump pump means connecting the pump to a pit in your basement or crawlspace, running discharge pipe to the outside of your home, and wiring the pump to power. The work is straightforward if you follow the order: dig or prepare the pit, set the pump, attach the discharge pipe, test the system, then seal everything. Most homeowners can do this in a day with basic tools — a shovel, a hacksaw or PVC cutter, PVC primer and cement, and a wrench.
Before you buy anything, check your local building codes. Some municipalities require a permit for sump pump installation, and some specify how far the discharge pipe must run from your foundation or where it can drain. A quick call to your city or county building department takes five minutes and saves you from having to redo the work later.
You will also need to know whether you want a submersible pump (sits inside the pit, quieter, more expensive) or a pedestal pump (motor sits above the pit, cheaper, louder). Submersible pumps are more common in new installations because they take up less space and last longer if the pit stays dry between uses.
Key Takeaways
- Dig a pit at least 18 inches deep and 24 inches wide, or use a pre-formed sump basin, and place it at the lowest point of your basement or crawlspace.
- Connect the pump discharge pipe to the outlet on top of the pump using PVC cement, then run the pipe to the outside of your home at least 4 to 10 feet away from the foundation.
- Install a check valve on the discharge pipe just above the pump to prevent water from flowing backward into the pit when the pump stops.
- Plug the pump into a GFCI-protected outlet or have an electrician run a dedicated circuit if the pump will run frequently.
- Test the system by pouring water into the pit to confirm the pump turns on, water drains, and the pump shuts off when the pit empties.
Prepare the Pit and Position the Pump
The sump pit is where water collects before the pump removes it. If you do not already have one, you need to dig a hole at least 18 inches deep and 24 inches wide at the lowest point of your basement or crawlspace — usually a corner or along the foundation wall. The pit should be deep enough that the pump sits below the floor level so water drains into it naturally.
If digging is not practical, buy a pre-formed plastic sump basin. These are 18 to 24 inches in diameter and come with a lid that has a hole for the pump discharge. Set the basin in the floor, level it, and backfill around it with gravel or concrete depending on your floor type.
Once the pit is ready, place the pump inside. If you are using a submersible pump, it sits on the bottom of the pit. If you are using a pedestal pump, the motor assembly stands on the floor next to the pit with the intake tube reaching down into the water. Make sure the pump is level and stable — a pump that tips or shifts will not work correctly.
Attach the Discharge Pipe and Check Valve
The discharge pipe carries water from the pump to the outside of your home. Most sump pumps have a 1.5-inch outlet on top. Measure from the pump outlet to where you want the pipe to exit your foundation wall, then cut PVC pipe to length using a hacksaw or PVC cutter.
Before you connect the pipe to the pump, install a check valve on the discharge outlet. The check valve allows water to flow out of the pump but prevents it from flowing backward into the pit when the pump stops. Without it, water will drain back into the pit and the pump will cycle on and off unnecessarily. Attach the check valve to the pump outlet using PVC primer and cement — explore primer to both the inside of the fitting and the outside of the pipe, wait 30 seconds, then explore cement and push the pieces together firmly for 30 seconds.
Once the check valve is set, connect the discharge pipe to the outlet of the check valve the same way. Run the pipe along the basement wall or through the rim joist to the outside of your home. The pipe should slope slightly downward as it runs away from the pump so water does not collect inside it.
Route the Pipe Outside and Away From Your Foundation
The discharge pipe must exit your home and run at least 4 to 10 feet away from the foundation — check your local code for the exact distance. The farther away the water drains, the less likely it is to seep back toward your basement or damage the foundation.
If the pipe exits through the rim joist or band board (the horizontal beam that sits on top of the foundation wall), drill a hole slightly larger than the pipe diameter and run the pipe through. Seal the gap around the pipe with caulk or foam to prevent air leaks and water intrusion.
At the end of the discharge pipe, attach a discharge elbow — a 90-degree fitting that points the water downward and away from the foundation. Some installations use a pop-up discharge head, which is a fitting that sits flush with the ground and pops up when water flows, then closes when the pump stops. This prevents debris from clogging the pipe and keeps the yard looking cleaner.
Make sure the discharge pipe does not drain directly onto a neighbor's property or into a storm drain without checking local codes first. Some areas have rules about where sump water can go.
Wire the Pump to Power
Sump pumps run on standard household electricity — either 115 volts or 230 volts depending on the model. The pump should plug into a GFCI outlet (ground fault circuit interrupter), which cuts power when ready if it detects a short or ground fault. This protects you from electrical shock if the pump or cord gets wet.
If you do not have a GFCI outlet near the sump pit, install one. A GFCI outlet looks like a standard outlet but has two buttons labeled "Test" and "Reset" on the face. You can buy one at any hardware store and install it yourself if you are comfortable working with electrical outlets, or hire an electrician.
If the pump will run frequently — more than a few times a month — consider having an electrician run a dedicated circuit from your breaker panel to the pump. A dedicated circuit means the pump has its own breaker and does not share power with other appliances, which reduces the risk of overload and extends the pump's life.
Do not use an extension cord unless it is rated for outdoor use and is the correct gauge for the pump's amperage. A cord that is too thin will overheat and create a fire hazard.
Test the System Before You Seal It Up
Before you close the pit or install the lid, test the pump to make sure it works. Pour water into the pit slowly until the water level rises to the point where the pump's float switch or pressure sensor should trigger it. The pump should turn on, water should flow out the discharge pipe, and the pump should shut off when the pit empties.
Listen for unusual noises — grinding, squealing, or rattling usually means something is wrong. Check that the discharge pipe is not kinked or blocked and that water is actually flowing out the end. If water is not flowing, the check valve may be stuck or the pipe may be clogged.
Once the pump runs and stops correctly, you can install the pit lid. Most sump basins come with a plastic lid that has a hole for the pump discharge and smaller holes for ventilation. The lid keeps debris out of the pit and reduces odors.
Common Mistakes to Avoid
The most common mistake is running the discharge pipe too close to the foundation or letting it drain into a low spot near the house. Water that pools near the foundation will seep back into the basement or damage the foundation over time. Always run the pipe at least 4 to 10 feet away and make sure it slopes downward so water does not collect inside it.
Another frequent error is forgetting the check valve or installing it backward. Without a check valve, the pump will cycle on and off constantly as water drains back into the pit. If you install the check valve backward, water will not flow out at all.
Do not plug the pump into a regular outlet without a GFCI. If the pump or cord gets wet, a regular outlet will not protect you from shock. A GFCI outlet is inexpensive and takes minutes to install.
Finally, do not skip the test. Running the pump before you seal everything up means you can fix problems while the pit is still accessible. Once the lid is on and the basement is finished, fixing a clogged pipe or a faulty check valve becomes much harder.
Frequently Asked Questions
Can I install a sump pump myself or do I need a plumber?
Most homeowners can install a sump pump themselves if they are comfortable using basic tools and following instructions. The work is straightforward — digging a pit, cutting and gluing PVC pipe, and plugging in the pump. If you are unsure about electrical work, hire an electrician just for that part. If you do not want to dig, hire someone to do the pit and you can handle the rest.
What size pump do I need?
Pump size is measured in gallons per hour (GPH). Most basement sump pumps are 3,000 to 5,000 GPH. If your basement floods frequently or quickly, a larger pump moves water faster. If water enters slowly, a smaller pump is fine. Check the pump's specifications and compare them to how much water your basement typically collects.
How often should a sump pump run?
A sump pump should run only when water enters the pit — typically a few times a month during wet seasons and rarely during dry months. If the pump runs constantly or multiple times per hour, the pit may be too small, the pump may be too weak, or water may be entering faster than the pump can remove it. Contact a plumber to diagnose the problem.
Do I need a backup pump?
A backup pump is a good idea if your basement is below the water table or if flooding would cause significant damage. Backup pumps run on battery power and turn on automatically if the main pump fails or if power goes out. They are more expensive but provide peace of mind in high-risk situations.
What should I do if the pump stops working?
First, check that the outlet has power and that the pump is plugged in. Pour water into the pit to see if the pump turns on — if it does not, the float switch or motor may be faulty. Check the discharge pipe for clogs or kinks. If the pipe is clear and the pump still does not run, the pump likely needs repair or replacement.