The DIY Guide to Replacing the Sump Pump without calling in the Plumber


Whether your old warhorse just gave up the ghost or your weak sump pump is sitting five feet below basement-filling water, it is never too late to learn how to replace a sump pump without calling in that cost-prohibitive plumber. Now you may well argue that staring down dark basement holes and handling PVC pipes may not be your cup of tea. We agree that this isn’t the pleasant of tasks, but with a little patience and some wise decisions prior to beginning the replacement procedure, it can become a short and easy procedure that can be managed with only the basic plastic cutting tools and a few cheap plumbing accessories.

Replacing the Sump Pump

Begin By Choosing a Good Pump and Matching Parts

If your existing pump died out after giving years of excellent service, it is best to go for a product of the same company and probably of the same product range as well. If, on the other hand, your sump pump collapsed because it couldn’t handle the water load, you’d have to go in for a beefier unit. While moving from 1/3HP to 1/2HP may be a simple equation, you should also consider:

  • Will the sump pump bump against the sides of my sump ?
  • Does it have special discharge requirements that would extensive replacement of PVC pipes/connectors ?
  • Will the float/impeller interfere with a secondary/primary unit I may have installed in addition to the one I wish to change ?

Once the pump has been chosen, it is time to go in for the parts that you would need. While these tend to vary a little (and you are at liberty to chop and change as you see fit), the basic parts required for a replacement procedure are:

  1. PVC pipe: Most pipes come with thicknesses of “1-1/2”NPT”. If the rest of the plumbing can remain work with the new unit, you would probably need no more than 2-3 feet of PVC pipes to replace the parts that have to be disposed along with the old unit.
  2. Check valve: Check valves prevent the backflow of water into the sump once the sump pump stops pumping and the pressure of water in the PVC pipe dies out. You can reuse check valves if you like but if you’re replacing an old sump pump it is best to replace the valve as well.
  3. Union Connector: This piece helps connect two pieces of PVC pipe easily and would be attached at the point where the old PVC pipe meets the new 2-3 feet of PVC that we shall use with the new unit.
  4. Screwdrivers, saw and safety equipment such as eye protection and gloves.
  5. PVC priming material and standard white cement.

Removing the Old Sump Pump

To remove your old sump pump:

  • Remove the sump cover and set it aside. Disconnect all power cords including those of any other sump pumps that may be present in the sump.
  • Locate an area of the PVC pipe exiting the pump that is convenient for you. This should generally be at a height where other pipes do not hinder manoeuvring of sharp and large tools.
  • Using a hacksaw, cut away the PVC pipe at the point you’d decided. While learning how to replace a sump pump be ready to get drenched by the residual water in the pipe.
  • Pull out the old sump pump using the handle of the pump (if one is provided) and set it down on a perfectly level surface.
  • Use a measuring tool to measure out the length of the PVC pipe.

Preparing and Installing the New Sump Pump

  • Use the measurements obtained to decide what length of PVC pipe you would need. Cut out the required length of PVC pipe using a hacksaw. It is wise to be liberal while cutting this pipe because cutting can fix overtly long pipes but a short pipe would require all sorts of connectors to operate properly.
  • Make another cut at a point that is just a little higher than the top of the sump when the pipe is placed vertically alongside the pump. Keep the piece of PVC that has been cut aside for now.
  • Use a male connector to place the PVC pipe we’ve just cut into the discharge of the sump pump.
  • Apply priming material and white cement to ensure that the pipe is firmly stuck. Leave the cement to dry out, preferably in the sun.
  • When the cement has dried, place the pump in a bucket full of water and connect the power cord. Notice how the water flows out of the small PVC pipe and falls back in a waterfall like movement. If any obstruction is noted there may be obstacles in the PVC pipe diameter and these need to be removed. A long narrow stick can be used for this purpose.
  • Once you are satisfied with the flow, it is time to take the new pump into the sump. Lower the pump gently into the sump till it is sitting on the most level surface possible. Ideally you should not need to shift any additional pumps that may be present in the sump to achieve this position.
  • Ensure that the float of the new pump isn’t in the way of any companion pump’s float or is not otherwise obstructed. Further, the sides of the pump should not be in contact with the wall of the sump.
  • Attach the valve at the tips of the PVC pipe One of the things you need to know when learning how to replace a sump pump is to keep the arrow indicator of the check valve in the right direction. Otherwise the valve will block the flow of all water and in doing so, would be rapidly destroyed.
  • Attach the remaining piece of the original PVC piece to the other end of the valve.
  • Use the union connector to attach the other end of the PVC pipe to the original PVC pipes of the basement.

Run a Quick Test of the Assembly

  • Pour a 5 gallon bucket of water into the sump. Such a high volume of water would usually flood the sump and cause the pump/s to kick in.
  • To check this, connect the power supply of the replacement unit and optionally, the other sump pump (if there is one) and turn power on.
  • Watch as water is lifted and taken out of the home without having to let a plumber into the house.

Replacing a Water-Powered backup sump pump

Battery-run units follow pretty much the same procedure as outlined above. For water-powered ones the procedure is similar but not exactly the same. To replace a water powered unit:

  • Restrict the water supply of the house or if that is not possible, the section that feeds the basement. This would be the municipal water supply in most areas.
  • Disconnect the inlet and outlet connectors of the pump and raise it out of the sump. Most units come with connectors that provide excellent interface between the pump and the water supply system. Reuse these if possible. The valves can also be reused.
  • Lower the pump into the sump such that only the switch mechanism is deep inside the pump. In most designs the remaining parts would be outside the sump.
  • Connect the inlet and outlet pipes and reconnect the water supply to the basement/house.
  • Run the 5 gallon bucket test and keep power of all other pumps disconnected. If the unit is still capable of removing water, you can now be sure that you’ve learned how to replace a sump pump.
  • Replace the sump cover.


Barring some extremely specialized designs, the above guide to learning how to replace a sump pump should stand good for all major sump pump variants. That said, the actual time required can vary if, for instance, the sump is very deep and it is not possible to make careful observations about the state of the float when looking down from above. In such situations, multiple test runs are required to figure out if anything is not working.

Nevertheless, it is true that knowing how to replace a sump pump is an important skill that can help you tide over many an emergency when even the costliest of plumbers isn’t available to help you out. In helping yourself by applying your knowledge to the replacement process, you can not only save some money, but also prevent sudden flooding situations. Hence, while we know that no guide is totally perfect, we do hope the above guide will take you one step closer to maintaining a dry basement all year round.



Bill is a DIY plumber, handyman, and homeowner with more than a decade of experience. He has replaced and repaired sump pumps, backup pumps, float switches, check valves, and many other things around his family home. An engineer and tinkerer at heart, he is always looking to see how things work and taking on new home projects that help him grow his skillsets. He is a husband and father of two boys, has a bachelors degree in Computer Engineer and minor in Mathematics and likes to make homebrew beer in his free time.

      Sump Pump Advisor