How to Replace a Septic Distribution Box

A septic tank in the ground.
  • 20-30 hours
  • Advanced
  • 5,000-10,000
What You'll Need
Distribution box
Plumbers putty
Carpenters level

The distribution box of the septic tank system is used to evenly distribute the wastewater from the septic system to the dispersal field. Over time, the distribution box can erode and will need to be replaced. This project is not difficult, but removing and replacing a distribution box is messy and grueling work. The article that follows will explain how to replace an old and worn out septic system distribution box.

Step 1 - Find the Distribution Box

This should be very easy to do, but it is not always the case. A distribution box is typically placed downhill, or at the base of a sloping area on the property. This is because they use gravity to collect and then distribute the water. If you were present when the distribution box was installed, then you will know where it is. If not, then contact the building permits office of your town, to get a copy of the plans, which will tell you the location of the distribution box.

Step 2 - Excavation

The distribution box is made out of concrete and is buried. Uncover the distribution box by shoveling away the dirt around it. Dig until you reach the bottom of the distribution box, and then expand your efforts, so that there is a foot of space around the box. You will also want to carefully dig out the pipes, exposing several feet of them.

Step 3 - Remove the Distribution Box

The box has several pipes going into it, which take in water and remove it to the leach field. Wiggle the distribution box, moving it toward the leach field, until the inlet pipes come off. Then, move the box back in order to remove the pipes on the other side, that lead toward the leach field. Once the distribution box is free, you can remove it.

Step 4 - Prepare the Ground

With the old box removed, you need to provide a flat area for the new distribution box. Use the shovel and the level to remove and then pack down dirt. Constantly check, until the floor of the space is level and flat.

Step 5 - Install the Distribution Box

Set the new box in place, by sliding it on to the pipes leading toward the leach field. The pipes should be inside the box. Line the septic tank pipes up with the distribution box, and then slide it back toward them, until they are inside the box as well. Adjust the distribution box, so that both sets of pipe are inside the box evenly. Once you are satisfied, place plumber’s putty around each of the pipes where they enter the box. Do this on the inside, as well as outside of the box. This seals the pipes, so that they will not leak. Once the putty is in place, replace the cover, and then rebury the septic tank distribution box.