Create a sump pump well with the plastic tub by placing the sump pump machine into the tub. For best results, place the tub in the basement below the washing machine and near an exit such as a window or basement door. Cut away the two knock-out holes in the tub to allow one pipe in and another pipe out. If possible, place the tub in an existing sump pump well or on a flat, level area on the floor.
Locate the PVC drain line for your washing machine. This pipe is usually against the wall or inside the wall behind the washer. The washing machine's black, flexible drain pipe is usually hung into the pipe. Remove the washing machine drain pipe and temporarily place it in a bucket.
Measure and cut sections of PVC pipe to create a new drain pipe for the washing machine that leads to the sump pump plastic tub. This new pipe system will stand parallel to the old system, allowing you to drain the washing machine's gray water to the sump pump or into the existing sewer or septic system.
Connect the PVC portions together with PVC cement, following the instructions on the cement container carefully. Allow the sections to dry.
Clamp the new PVC pipe to the wall behind the washer and next to the existing PVC drain pipe with pipe clamps and screws Place a flexible short cap specially made for PVC pipes over the existing sewer or septic drain pipe. This cap prevents sewer gases from entering the house when you use the gray water drain system.
Wrap a loose quantity of nylon stockings or cheesecloth to the end of the washing machine drain pipe to create a loose bag. Use rubber bands to secure the material around the end of the pipe. Use this material to catch lint and other debris from the gray water to prevent particles from entering the gray water pipe line and sump pump, where debris can cause damage to the pump. Remove the material from the pipe whenever you place the washer drain pipe back into the existing PVC sewer or septic line.
Connect the end of the new PVC pipe system to the intake valve on the sump pump appliance in the plastic tub. Read the sump pump directions carefully, as pump and pipe connections vary, depending on the manufacturer.
Measure and cut sections of PVC pipe to create the distribution pipe system. Depending on your use of the gray water, you can either connect the PVC pipes to corrugated and perforated black pipes for an irrigation system or connect a longer section of PVC pipe and divert the gray water to a dry well system or other waste water system approved for use in your region.