How To Fix A Clogged Bathroom Sink

There are various points in your drain where a clog or other obstruction may occur, causing your bathroom sink to drain slowly or not at all. If your sink begins to fill with a black foul smelling substance without running any water, call an emergency plumber immediately. Your sewer system is backed up and raw sewage is coming into your home, along with the possibility of poisonous and explosive methane gas.

However, if you have a simple drainage problem, there are many solutions that you should try before calling in a professional.

Where should you look for a sink clog?

Sink strainer

If you have a wire mesh strainer in your sink drain opening, you should start by inspecting and cleaning it. Hair, toothpaste, and soap scum can begin to accumulate on the strainer, forming a blockage that will not allow water to pass.

It's a good idea to have a brush for cleaning baby bottles on hand for this task and to use it to clean the strainer on a regular basis. While you can clean the strainer with a paper towel, the contents will likely be disgustingly slimy.

Sink trap

This "J" shaped fitting that connects the sink drain to a branch pipe of the main drain serves a dual purpose. It collects debris that may form a clog in a more inaccessible area in the drain, and because it remains filled with water at all times, it blocks dangerous sewer gases from entering the home.

You can remove and clean it by loosening the large plastic nuts on either end. Just keep a bucket handy to place the trap in when you remove it, and keep it upright at all times, because it will likely be filled with sludge and dirty water.

You may face resistance when cleaning the trap if it is filled with tightly-packed sludge. If you decide to clean it by running water through it in a different sink or a bathtub, be sure to block the drain so none of the clogging agents clog another drain.

Before reconnecting the sink trap, wrap a few layers of Teflon tape in a clockwise direction around any exposed pipe threads, and then tighten the two plastic nuts.

If your sink is still clogged or draining slowly after cleaning the strainer and sink trap, it's time to use some muscle.

Plunging your sink drain

Before you attempt to use a plunger on you bathroom sink, check the drain pipe that is connected to the smaller end of the sink trap. If the pipe drains into an opening in a branch pipe in the floor, check to see that a compression nut is being used to seal the opening.

Some sinks simply have a drain pipe that slides into a floor opening, which is fine if the drain beyond the opening is clear. However, if it is clogged, and you create pressure in the drain line by using a plunger, water will be forced backward and out of the drain opening in the floor, flooding the floor and the ceiling below with water.

If no compression nut is present, you must install one before plunging your sink. You will need a 1 1/4" compression nut for a bathroom sink (kitchen drains use a 1 1/2" drain pipe). The compression nut has a washer inside that seals an opening between two smooth pipes when a smaller pipe is inserted into a larger pipe for draining.

To install a compression nut, you will need to loosen the nut on the bottom end of the sink trap and pull the drain pipe loose from the trap. You will then lift the drain pipe from the connection in the floor and place the compression nut on the end of the pipe.

Insert the pipe into the floor drain again, sliding the compression nut up the pipe until the pipe is fully seated. You will then slide the compression nut down until it reaches the floor drain fitting, then start to tighten the compression nut over the floor drain fitting. You will need a large wrench to tighten the nut sufficiently to create a proper seal.

You can then reattach the sink trap and start to plunge. Never use drain cleaners before using a plunger, because splashing and serious burns can result.

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