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Sump Pump Installation (A Step-by-Step Guide)

How to Install a Sump Pump

Many older homes were designed with inadequate basement waterproofing, making them more susceptible to floods. Sump pump installation is one way owners of at-risk homes can protect themselves against damaging basement floods and other water leaks that might occur. If you consistently have water in your basement then the most practical solution might be to install a sump pump.

Do You Need a Sump Pump?

It’s quite possible that the water in your basement is the result of poor outdoor drainage, not a problem with your basement’s construction. Before installing a sump pump check for other issues that may be causing the problem.

  • Check your gutters for clogs, specifically in and around the downspouts. If water isn’t able to flow freely it will spill over from your gutters and build up around the edge of your basement. An abundance of leaves that build up and prevent water flow is the most common (and easily fixed) problem with gutters.
  • Even if your downspouts aren’t clogged they still may be causing a problem. Check to make sure they are depositing water four to five feet away from the foundation and that the water isn’t flowing back towards your home.
  • Inspect the land surrounding your home.  Make sure that the soil within three feet of the basement slopes away from the house.

If you’ve inspected the outside of your home and have determined that none of the above issues are causing the problem then it’s likely the leaking issues are due to the local groundwater level being too high and forcing water upward through the cracks in the foundation into your basement. This, coupled with poor basement waterproofing, means installing a sump pump is recommended.

What You’ll Need:

  • *Electric jackhammer (you should be able to rent one for about $8 an hour)
  • Float-activated submersible sump pump (about $75-125)
  • PVC pipe and fittings
  • Pit liner
  • Gravel
  • Cement

*Instead of the electric jack hammer you can also use a heavy duty hammer drill with a masonry bit, a sledgehammer and a masonry chisel. You could also use a demolition saw designed to cut concrete, although these usually create a lot of dust. An electric jackhammer isn’t too expensive to rent and is by far the easiest way to remove concrete.

Sump Pump Installation Step 1: Preparation

Before installing a sump pump you will need to find out if it’s possible to do so on your land. Most of the homes built over the last thirty years were constructed on top of gravel, but you will want to be sure (or as sure as you can be) before digging a sump pit in your basement. Get in contact with the builder of the home if possible, or ask neighbors with homes built roughly the same time as yours. Unfortunately, in some cases, you simply won’t know what lies beneath your basement until you start digging your sump pit.

Another thing to consider is the timing of digging a sump pit inside your basement.  Do not dig the sump pit during a raining season or shortly after when groundwater level is higher than usual. Digging a hole through the concrete foundation may cause water to rush into your basement without any resistance. Therefore, you will want to install the sump pump during a dry season when the groundwater level is relatively low.

Next, you’ll have to find a good location for your sump pit. The ideal location is about 8” away from the basement wall in an area where you can punch a hole through a rim joist to get through the floor. Make sure the sump pit is well clear of the sewer line. Some homes also have water lines running underneath them which presents another obstacle to be aware of. Most water lines that are under the floor enter from the street, usually four to six feet from the sewer pipe. If you’re at all unsure about where these lines are check the building codes in your area or employ the services of a surveyor.

Use the sump liner to trace an outline on the floor so you know how big to make the hole. A good rule of thumb is to leave a three to four-inch gap around the liner when tracing it to ensure the hole will be big enough. You can fill this gap with gravel and concrete once the liner is placed inside.

Sump Pump Installation Step 2: Removing the Concrete

The next step is to break through the concrete foundation. The easiest way to accomplish this is to use an electric jackhammer. Cut the concrete into manageable square pieces, about 8 – 12 inches in diameter, and then move the jackhammer at an angle to pry them up and carry them away in a bucket. Try to avoid shredding the concrete, as this will create a bigger clean-up.

If you’re unable to get access to an electric jackhammer, you can make do with a hammer drill rigged with a masonry bit, a good sledgehammer, and a masonry chisel. Use the masonry bit to make holes every few inches in the concrete, then use the hammer and chisel to crack the concrete between the holes. As with the jackhammer, you will want to cut the concrete into manageable pieces that can be removed.

Some floors may have a steel mesh installed in it, which will require a pair of heavy wire cutters or a metal grinder to cut through it.

Sump Pump Installation Step 3: Digging the Sump Pit

Once the concrete is removed you can begin digging the sump pit. You’ll want to dig the pit 12 inches deeper than the sump liner, then fill the bottom of the hole with coarse gravel (use gravel with an aggregate of 3/8 to ½ inches) to promote good drainage. Make sure there is enough gravel in the hole so that the line sits flush with the basement floor.

It might be necessary to drill some holes in the liner to allow water to get inside and be pumped out. Make sure the diameter of these holes is smaller than the size of the gravel so that no gravel will enter the sump liner.

Insert the liner into the hole and place more coarse gravel around the edges, leaving six inches between the gravel and the floor. Once the liner is in place, pour a 6-inch layer of concrete over top of the gravel. Mix one part cement, two parts sand and three parts gravel, and then add water. Use a trowel to smooth out the top so it’s flush with the floor and the liner.

Wait until the concrete has set (at least eight hours) before moving onto the next step.

Sump Pump Installation Step 4: Installing the Pump

Most sump pumps will have a 1 ½ inch diameter threaded discharge port, but refer to your pump’s instruction manual to be sure. Start by threading a 1 ½ inch PVC male adapter into the port. Tighten it with pliers until it feels snug. Next, use PVC cement to glue a schedule-40 PVC riser to the adapter. The length of the riser will depend on the height of the pit liner you’ve installed. You want the top of the riser to be just above the top of the liner.

Place the pump inside the liner. Once the pump is in place you’ll have to set-up the check valve. This is used to expel the water left in the tube after the pump turns off, preventing the motor from burning out. The valve should come with rubber couplings and hose clamps. Be sure to position the valve with the arrow pointing up and then tighten the lower coupling over the riser with a screwdriver.

Sump Pump Installation Step 5: Moving Outside

Create a path to feed the PVC from your basement to the outside of your house. The easiest way to do this is to bore a hole through the rim joist. Use a hole saw to cut a hole through your siding and rim joist. To make sure you drill in the right spot start by drilling a ¼ inch hole through the rim joist and siding from the inside. Find the hole outside and then use a 2 inch bit to drill the finished hole from the outside.

Next, assemble the PVC piping from the check valve to the hole you’ve created. Be sure to dry-fit the piping before gluing anything. Complete the seals with a caulking agent on both the inside and outside contact points. Once the pipe is outside cut it so only ½ an inch is poking out. Then, glue a 90-degree elbow to the end of the pipe so it points downward. Connect a hose to the piping outside to take the water away from your home.

Sump Pump Installation Step 6: Test Your Pump

Finally, dump some water into the sump pit and test out your set-up. Check for any leaks in the piping and make sure the water is being deposited away from your house and not flowing back towards it.

For more information on sump pumps, watch the following video: