This post will help you understand what type of bathtub drain pipes you have. This is the first step in understanding how to unclogging the tub drain. There are two pictures which show the types of tub drains. The first picture is referred to as a u-bend or p-trap style tub drain. The second is the first type or oldest of tub drains called a drum trap. First, look at the drain fittings connected to and just outside the tub. You might do this from the room below the tub or by taking off the access panel on the other side of the wall where the faucet is mounted. In older Minneapolis homes the access panel is in the closet.

Drain: U-Bend or p-Trap Diagram

normal configuration of tub pipes with a p-trap

A u-bend trap has a vertical pipe going into a “U” shape and then going horizontal (the trap “arm”). If the tub has a u-bend trap, this is easier to clear than a drum type trap. I can usually clear this type of line because it is simple to open up an access to the drain and use a standard metal “snake” to clear the clog.

tub with a Drum Trap Diagram

Diagram of a tub with a drum trap.

Occasionally the home still has a very old device called a drum trap. In this picture the “box” on the left depicts what is actually a cylinder about 4 inches in diameter, 6 inches tall. It has a pipe entering the side (the outlet) and one coming straight into the bottom. This is device original to the home when it was built. In order to mechanically clear (“snake”) a drum trap it requires the removal of the drum cover because a metal “snake” cannot be inserted through the right angle fittings before the drum. This is a difficult and problematic process even for an expert drain technician. Opening and then resealing a drum trap requires a series of specialized tools, techniques and parts.