The short answer
Assess the Low Spot
Before buying a pump, look for the lowest spot where water pools after rain or a plumbing leak. In an old home, that spot may be uneven or near a foundation crack. Use a level to find the true low point, and check the floor for dampness or efflorescence, which signals water seepage.
Also measure the distance from that low point to where you can route discharge water away from the house, such as a storm drain or a downhill area. That distance determines the pump's lift capacity. If the space is tight or the foundation is fragile, local water damage pros can assess the area first.
Prepare the Sump Pit
You need a basin that holds water and the pump. For an old home, a plastic or fiberglass sump liner is easier to set than a concrete pit. Dig a hole about 18 to 24 inches deep and wide enough for the liner, ensuring the top is flush with the floor.
Place a layer of gravel or sand at the bottom to keep the pump intake clear of sediment. If the floor is cracked, seal those cracks with hydraulic cement before setting the liner. This prevents soil from washing into the pit and keeps the pump from clogging.
- Check for existing drain tiles or old pipes that might route water
- Use a sump liner with a lid to keep debris and animals out
- Test the floor slope with a long level
- Seal any visible cracks with hydraulic cement
- Keep the pit away from load-bearing walls if possible
Choose the Right Pump
Select a submersible sump pump with a float switch that turns on automatically when water rises. The pump's horsepower and head lift must match your discharge distance and height. For a typical old home, a 1/3 or 1/2 horsepower pump handles most water volumes.
Check the pump's voltage and cord length. Old homes may have a 15-amp circuit, so verify the pump's draw. If you have frequent high water, a pump with a tethered float is more reliable than a vertical float. If unsure, consult an electrician for wiring requirements.
Install the Discharge Piping
Run a rigid PVC pipe from the pump up and out of the pit, then slope it downhill to the discharge point. Use a check valve near the pump to prevent water from flowing back when the pump shuts off. Support the pipe with hangers so it doesn't sag.
Make a hole in the wall or floor for the pipe, then seal around it with waterproof caulk. Keep the discharge point away from your foundation and any septic system. In areas with heavy rain, a reliable discharge route matters, so plan the pipe slope carefully.
Wire and Test the System
Connect the pump to a dedicated GFCI-protected circuit. An old home may have outdated wiring, so have an electrician inspect the breaker box first. Never plug a sump pump into a regular outlet that could overload. Follow the manufacturer's wiring instructions carefully.
After wiring, fill the pit with water to test the float switch. Watch the pump cycle on and off, and check for leaks in the discharge pipe. Run the test several times to ensure the float doesn't get stuck. If water doesn't drain properly, adjust the float or pipe slope.
- Use a GFCI outlet for safety
- Test the float switch by raising it manually
- Check the check valve for proper direction
- Inspect the discharge pipe for frost damage in winter
- Keep a spare float switch on hand
- Clean the pit inlet screen regularly
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Call Now (469) 698-4610Frequently asked questions
Can I install a sump pump myself in an old home?
Yes, if you are comfortable with basic plumbing and electrical work. However, old homes often have uneven floors and outdated wiring. If you notice cracks or suspect foundation issues, consult the pros to avoid making the problem worse. Always test the pump after installation.
What size sump pump do I need for a low area?
The size depends on the water volume and the vertical lift to the discharge point. For most residential low areas, a 1/3 horsepower pump with a 10 to 15 foot lift works. Measure the height and distance, then check the pump's spec chart. If you have frequent flooding, a larger pump may be needed.
How often should a sump pump run?
A sump pump should run only when water enters the pit, so frequency varies. In dry conditions, it may not run for weeks. During heavy rain or a plumbing leak, it might run every few minutes. If the pump runs constantly, there may be a high water table or a leak, so inspect the pit and the surrounding area.