How to Replace a Bathtub Drain Pipe

  • 2-3 hours
  • Intermediate
  • 400-500

Corrosion and clogging are the major reasons that lead to the replacement of the bathtub drain pipe. The steel pipes of the drain eventually rust and crack causing leakage which in turn lead to their replacement. It would take about three hours to completely replace the drain pipe. By replacing the pipes yourself, you will be able to save the cost of hiring a plumber by following a few simple steps.

Tools and Materials Required

To replace a bathtub drain pipe, you will need cement, drain pipe, drain wrench, hacksaw, measuring tape, paper, and tub drain kit.

Step 1 – Purchasing Drain Pipe

Take the measurements of the drain pipe and drain hole. Note down the measurements and use them to purchase the pipe of proper length and diameter. Also, buy a good quality drain pipe since it will last longer. Make sure you meet all local plumbing ode requirements while choosing the pipe.

Step 2 – Detachment of the Assembled Parts

Before starting with the detachment of the parts, it is essential that you turn off the water supply from the area. Now, locate the area where the drain pipes are located. They are mostly found behind the tub. Once they are found, detach the drain pipe and over flow trim from the tub with the help of a drain wrench. Remove the bathtub and set the tub down on a hard, balanced surface.

Step 3 – Cutting and Fixing Drain Pipe

Measure the drain hole from the inside of the tub to the surface the tub rests upon. Note the measurement. Now, measure the new bathtub pipe by placing it next to the old pipe. Use a hacksaw to cut the extra length. It should easily line up to the holes of the bathtub. Or use a sanitary tee and cut a pipe that fits from the outlet of tee to the fitting of the drain. Make sure the hole in the tub meets the drain fitting. Also ensure that the overflow and drain fitting should be facing each other before fastening them to the drain pipe. It is a trial and error process and may need repeated adjustment. When it fits perfectly, join them with cement.

Step 4 – Fit P-Trap

P-Trap is a pipe that will connect the waste pipe and the overflow pipe to one main pipe. It comprises of a drain elbow that fits into the drain pipe, a curved trap piece and a tail piece. Fit the drain and overflow pipe with P-trap. They should be at a specific distance from the top of the drain fitting. You may need repeated cutting to make small changes.

Step 5 – Reattach the Bathtub to Pipes

Mark the area of the floor where the center of the tub will lie. This will indicate the drain fitting location. After this, place the center of the tub over the marked drain fitting. Fix it in place. If the pipes have fitted perfectly, they will match the holes in the tub. Now, attach the overflow and drain pipe to the tub with the help of a drain wrench. Once that is done, place tub drain rubber gasket and then the tub drain flange in their respective areas. Turn on the water supply after everything has been fixed. Once you ensure there is no leakage, you can store away the tools and clean up the work area.