Installing Submersible Water Pumps

Learn How To Install a Sump or Ejector Pump for Better Water Drainage

Drain pipe

The two types of household pumps that are the most common for homeowners to deal with are sump and ejector.  They are both designed to help with water drainage. This article will teach you the basics of replacing these pump:

  • Sumps pump rain and ground water out of our basements preventing flooding. A simple pit would be a hole (plastic pit with holes drilled in the bottom) in the basement floor that would fill up with water as the ground becomes saturated, and when the water in the hole gets high enough a pump kicks on and pushes the water up a discharge pipe that leads out to the lawn or another acceptable destination. Building codes have come to require drain tile (usually a 4" corrugated plastic pipe) to run around the perimeter of the house's foundation under the concrete basement floor and to be tied into a sump pit when a house is built. The drain tile has slits in its walls so that as the ground water rises up under the basement floor, the water seeps into the tile and runs downhill into the pit to be pumped out. When the drain tile is installed, it is buried in a bed of gravel to facilitate the flow of water seeping to the slits, and with fabric covering over the tile to prevent silt from entering the pipe. Sump pumps are usually equipped with a 1/4 or 1/3 HP motor and come with either a plastic or cast iron housing, the 1/3 HP cast iron pump being the most expensive. Sump pits usually have a loose fitting cover. The pumps have a discharge opening of 1 1/4" or 1 1/2" and are plumbed with 1 1/2" PVC pipe.
  • Ejectors pump dirty water generated by our household activities into a sewer or septic system. Most come into play when there is going to be some kind of plumbing waste water produced in the basement and the sewer line of the house is located above the basement floor. The most common producers of waste water are bathrooms, central A/C condensate lines, hot water heaters (servicing of the heater), washing machines, and laundry tubs. For sanitary purposes, ejector pits must be sealed with an air-tight cover. Ejector pumps are usually equipped with a 1/3 or 1/2 HP motor and also come with the plastic or cast iron housings with a 2" discharge opening.
  • Check valves are one-way valves that allow water to pass through in one direction only and are required with both types of pumps. They consist of a simple flapper that flops up as water is pushed up the discharge pipe, but when the pump shuts off, the water in the pipe that hasn't made it outside gets pulled back down toward the pit by gravity, pushing down on the flapper and sealing it shut. They are installed a few feet above the pit in the vertical discharge pipe. Be sure when installing to check the flow arrow marked on the valve to make sure it is aiming in the right direction.

Remove the old submersible water pump.

  1. Unplug cords. There are two cords plugged into the outlet from the pump: the cord from the switch that is plugged in first and the cord from the pump motor that is plugged into the backside of the switch cord. Unplug both from the outlet.
  2. Remove valve. Loosen the clamps that fasten the check valve to the discharge pipe, and then remove the valve.
  3. Remove pit lid. Slide the pit lid up over the discharge pipe where the check valve was located, and set it aside.
  4. Remove pump. Grab the discharge pipe sticking up out of the pit, pull out the pump and set on the floor.
  5. Discharge pipe. Since most pumps are similar in shape, you will have a good chance of reusing the old pipe and fittings. Using a large channel lock pliers or pipe wrench, unscrew the discharge pipe from the old pump.

Install new pump

  1. Assess discharge pipe. Set the new pump on the floor and measure the distance from the floor to the top of the pump outlet where the discharge pipe screws into. Compare it to the measurement of the old one. If they are within 1/2", you will be able to use your old discharge pipe; if not, you will have to cut a new one to the proper size gluing on a new threaded adaptor on the bottom of the pipe.
  2. Install discharge pipe. Screw in the discharge pipe into the pump base using teflon tape on the threads.
  3. Add the new pump. Lift the pump up by the discharge pipe and lower it into the pit, lining up the discharge pipe with the other pipe hanging above. Be sure to spin the pump in the pit so that the switch float (the black ball hanging on the side of the pump) can move without hitting the side of the pit.
  4. Replace cover and lid. Slide the cover over the discharge pipe, pull the electric cords through the slot in the lid and drop the lid down onto the pit.
  5. Reconnect the check valve, making sure the arrow is pointing away from the pump.
  6. Plug in the cords. Check to see if your sump pump installation works.

Ejector pumps are installed with the same procedure as above with two additional steps.

  1. Unbolt the lid. The lid of the ejector pit is bolted down with a foam rubber seal between the lid and the pit. Using a socket wrench, you will have to remove the bolts from the lid to lift it up. And if the rubber seal is too dilapidated to reuse, you will have to purchase a new seal from the hardware store. There are also seals around the pipes that come out of the pit held down by two screws that hold the pipes secure in the lid, as opposed to the sump lid that has the pipes loosely penetrating the lid.
  2. Disconnect and reconnect the vent pipe. When you look at an ejector pit, you will see two pipes coming out of it. Because the ejector pit is airtight, when the pump removes water from the pit it creates a vacuum that would suck out the trap water of the fixtures plumbed to the pit, which would allow sewer gas to permeate the home. To stop this from happening, a vent pipe brings air into the pit to counter the vacuum, and is usually connected to the main plumbing vent of the house. It is common practice to have a rubber hose (looks like a piece of radiator hose) with clamps on it located on the vent pipe at the same height as the check valve, so that when you disconnect the hose, there is a break in both the discharge pipe and the vent pipe where you can easily lift the lid off. If there is no hose on the vent, you will have to cut the pipe at the same height as the check valve and reconnect the vent with hose or a PVC coupling.

The pumps described here are submersible pumps, where the whole pump is underwater in the pit. There are also pedestal pumps where the motor is raised above the base out of the water. They are not as prevalent anymore because of the noise the motor makes outside of pit and the difficulty in covering it.

If a submersible pump is not working, the motor can be tested by pulling the motor plug out of the back of the switch plug and replugging it directly into the outlet. If the pump is working, it will go on immediately. If the motor works, the float may be hitting the side of the pit. Plugging the motor cord back into the switch plug, then manually reaching into the pit and moving the float up and down, will tell you if the switch is working. Many pumps have replacement switches available.


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