I received a question from Samuel C. asking: “I have a constant smell in my bathroom I can’t seem to find or fix. Any suggestions?”
Yes…. Flush when you’re done.
No, I’m kidding Sam.
What you are most likely smelling are sewer gasses. All of the drains in your bathroom lead to a central drain that takes waste-water out of your house to either a city sewer line or a leach field depending on where you live. Those drain lines can contain sewer gasses such as Methane, hydrogen sulfide, ammonia, sulfur dioxide and more.
The way we stop those gasses from coming back into your house is by means of a “trap”. What’s a trap?
A trap is when a woman asks you if an outfit makes her look heavy….. It’s also a U-shaped bend in the drain line that “traps” water creating a barrier between you and the open sewer system.
The Usual Suspects:
In a full bathroom there are typically three traps:
One under the sink (which is often located in the vanity cabinet)
One under the tub/shower (which is usually hidden in the floor)
One in the toilet (This one is actually built into the toilet itself)
One or more of these could be causing that smell. Typically, if a sink trap is faulty, you will see signs of water damage below the trap suggesting it’s not holding water as it should. That would show up in the vanity cabinet floor. For the tub/shower it can be trickier as the trap is enclosed and may show signs of leaking in the ceiling below if it’s a second floor bathroom.
All of that being said, the first place I always check and the most likely candidate is the toilet and let me explain why.
As I mentioned, the toilet has a built-in trap. This trap allows the toilet to maintain the water level inside the bowl. If there was no trap, the water would just flow down the drain and the toilet bowl would be empty and dry. When a toilet is installed, it’s placed onto a floor drain using a wax ring gasket.
The wax ring is used to seal the drain outlet on the bottom of the toilet to the drain opening in the floor. When a toilet is installed, the ring is placed onto the drain… the toilet is dropped onto the ring… and the toilet bolts (also known as closet bolts) are tightened enough to lock the toilet in place. If that wax gasket ring starts to fail or isn’t seated properly? Sewer gasses can sneak out from under your toilet causing your bathroom to have that suspicious smell. It can also cause water to escape, sometimes invisibly, with each flush potentially damaging the floor hidden under the toilet.
How To Repair A Toilet Gasket:
1) Turn off the water supply to your toilet
2) Flush the toilet and hold the handle down to drain as much water from the tank & bowl as possible
3) Disconnect the water supply line
4) Disconnect the two closet bolts holding the toilet to the floor
5) Lift the toilet straight up and off and place it to the side. Try to lay either old towels or a drop-cloth underneath as the wax ring can be stuck to the underside and make a mess of whatever it touches. Also, It’s hard to get all of the water out of the toilet without pumping it and any tilting will cause it to spill out from underneath.
6) You’ll now see the drain flange on the floor. Scrape any excess wax off of the flange to prepare it for a new wax ring.
I suggest buying a jumbo ring with a built-in flange to get the best seal. They often come with new closet bolts in case your old ones are junk.
7) Be sure to inspect and clean the bottom outlet of the toilet to remove any excess wax that may be stuck to the toilet. BE CAREFUL! As I mentioned, when you tip the toilet excess water WILL spill out. I like to take the toilet into the tub or shower for this maneuver if possible. Also, the wax the rings are made out can make a mess of things it comes in contact with. Do your best not to get it on you, your floors, your dog…. your children.
8) Set the new wax gasket in place on the floor, position the closet bolts so they are straight up and ready for the toilet.
9) Drop the toilet in place making sure the bolts slide up through both holes in the base of the toilet and press down. You should feel the toilet raised from the floor as you press it down a bit into place till the base touches the floor. That’s the wax gasket ring getting squished down and creating the seal you need. If the toilet hits the floor with a clunk, the gap between the drain flange and toilet outlet may have been to big for the wax ring to seal. You may need to stack a secondary standard wax ring on top to create a seal (this isn’t ideal, I’d rather have a new toilet flange installed at the proper height but, it’s not uncommon).
10) Tighten down the closet bolts making sure NOT to use too much torque. You aren’t installing tires on a race car here so, take it easy Mr. Goodwrench. You just want to hold the toilet in place, not crack the porcelain base of the toilet or damage the drain flange.
11) Reconnect the water supply, turn on the water and let the tank fill back up.
12) Flush a few times to make sure things are sealed and no water is leaking out and voila…. you’ve successfully re-installed your toilet with a proper seal.
Sometimes there can be complications of broken toilet flanges, closet bolts or rotted sub-flooring. If you find any of that in your situation, it will need to be repaired before reinstalling the toilet.
Best of luck and if you have any other questions, be sure to Ask A Home Improvement Expert!
