How to Get Rid of Drain Odor
What is that smell coming from the drain? Well unfortunately it is the odors not only from your household’s drain waste, but your neighbors too! Thinking about it can make a person nauseous. So what can we do to stop the stink without having to call a plumber? Let’s take a look:
The P Trap Problem
Odors coming from sinks and washtubs are usually caused by a P Trap that is emptying or drying out. Take a look under the sink to see that part of the drainpipe that is actually “U” shaped, the way it is positioned, but is referred to as a P Trap. That little piece of pipe is supposed to hold a tiny bit of water after the sink drains to act as a seal against sewer gasses backing up into the room. If it doesn’t have any water in it, the gasses travel up the pipe into the room, and then up your nose where the yuck factor comes in.
Common causes for that little section of pipe to not have water in it are sinks that are not used often so the water in the P Trap evaporates, or plumbing systems that aren’t vented properly. The first is easy to fix by running a bit of water down the sink occasionally to refill the trap with water. That will block any gasses from the sewer from coming up into the sink. The second is a bit more involved, but not that difficult to remedy.
Installing a Vent
If the venting of the plumbing system has never been correct such as can be found in some older homes, draining a sink can create a vacuum effect caused by the water traveling down the drain. Normally a pipe that goes up through the roof will let air in behind the draining water. If that vent pipe is not there, or is clogged, this causes venting problems with the plumbing.
Sometimes sucking sounds can be heard from sinks or toilets when they are drained or flushed. This is a result of the vacuum. The proper way to fix it is to have a plumber fix the main vent pipe or pipes, but a homeowner can rectify the problem at individual sink drains by installing a one-way vent. Check your codes about doing this yourself.
After the P Trap there should be a length of pipe going into the floor or wall. This is where you would install the vent. Just get some plastic fittings including the vent that will allow you to attach it in the section of drain after the P Trap. Usually you will need a T fitting, a small piece of pipe, the vent, and some pipe glue.
Most under-sink drains can be disassembled by hand. Take a picture or draw the drain as it is before the changes. Measure the piece of pipe after the P Trap. Cut out a section the length of the T fitting minus how far the pipe will stick into the T fitting on each end (you need this length to fit pipe into the T fitting for gluing).
Cut a small piece of pipe to fit into the side part of the T fitting. Attach the vent to the end of this piece of pipe. Check to see if everything will fit before gluing. Glue according to the instructions on the adhesive product. Put it all back together hand-tight. Check for leaks with hot water.
Take a picture of your drain to the store where you will be buying the parts. You might be able to get fittings that do not require any gluing. Just use a bit of common sense, stay calm, think it through. It’s just a few pieces you are fitting together like a puzzle, and it is just a sink drain. It’s not like you are doing surgery!
The vent will allow air into the system, but won’t let fluid or gasses back out. Depending on the vent, it may have to be in a vertical position. Just ask the salesperson or read included literature.
Some Drain Odor is Sludge
Some sinks have a thick buildup of bacteria laden sludge that is in the section of the drain before the P Trap. A quick way to manage these odors is to remove the pop-up drain that most sinks have by giving it a slight twist, and pulling up. It should come loose from the rod that holds it in place with a quarter or half turn in one direction. Don’t force it. Pull up on it when it comes loose. Put it back by following these instructions in reverse.
With the pop-up drain out, use some baking soda and an old toothbrush securely taped to a wooden dowel with strong tape such as electrical tape. The dowel and toothbrush should fit in the drain and go down as far as the P Trap.
Scrub the pipe with the baking soda. Rinse with hot water. Repeat until clean enough that sludge and odor are gone. Clean the pop-up drain with the brush and baking soda as well. Reinstall the pop-up drain.
Bacterial colonies growing in the sludge buildup need to be manually removed. Using chemicals such as bleach only get the surface bacteria, but the sludge stays behind to grow new bacterial colonies.
Basement Drains Gone Bad
Many an older home has a basement drain in the middle of the floor that stinks like grandpa after he has eaten a few burritos. If you can’t afford a plumber, try a test plug. Check your codes first, and consider the risk of the drain being plugged. If there is any concern of flooding either from outside the home coming in, or a pipe that may burst, then the owner must decide whether or not to use this inexpensive fix.
A test plug is a rubber stopper with a metal back plate and wing nut assembly. The plug is meant for pressure testing new plumbing systems, but the plug also works very well to temporarily seal a basement drain. The plug can be easily removed by loosening the wing nut. A hacksaw may be needed to shorten the post where the wing nut is so that the drain cover can be replaced.
Buy a test plug of the proper diameter for the drain pipe. Press the plug into the drain. Tightening the wing nut puts pressure on the rubber washer causing it to expand outward. This expansion holds the plug in place preventing sewer gasses from backing up into the basement at this drain. A solution that works like a champ, but is not for every circumstance.
There is a lot the average person can do to rectify drain odor problems without needing to call for expensive plumbing repairs. If you have the means, then let the professionals handle it. If your are on a tighter budget, try some simple solutions such as the ones in this article to get rid of drain odor problems.