Eliminating an ammonia smell in the bathroom can be an easy fix, or the smell might indicate a more serious issue that will require some work on your part, or even the assistance of a plumber. To find out which you're dealing with, start by checking for simple solutions to the problem. If the odor persists, you may be dealing with something more serious.
A Thorough Cleaning
An ammonia smell in the bathroom may simply be the remnants of a pet accident or poor aim by the boys and men in the family, since the ammonia smell is most commonly caused by urine. Thoroughly clean and disinfect the toilet and the area around it to make sure any urine splashes or misses are cleaned up. If you have any pets who may have had an accident in the bathroom, clean and disinfect the entire floor rather than just the area around the toilet.
Check Your Drain Traps
The drain traps—the curved pipes in the bottom of your sinks and toilet bowl—are designed to keep sewer gases out of the house. The curved trap holds water in the pipe, creating a physical barrier to gases rising up from the sewer system. When you do not use the toilet or sink for a long time, the trap will dry out, opening a pathway for gases to enter your home. How quickly the trap dries out will depends on humidity levels in the house and how frequently the plumbing is used. You can prevent this from happening by flushing rarely used toilets periodically and running water through unused sinks to keep the trap full.
Bacteria that live in the sewer may find a way through the toilet's trap, especially if it dries out for a period of time, and they may take up residence in the bowl. Usually they will live just under the rim, by the portholes where the water from the tank drains into the bowl each time you flush. The rushing water over these bacterial colonies can let off some foul smells. A toilet brush and toilet cleaner typically does not eliminate the bacteria. Instead, pour several cups of bleach down the toilet's overflow pipe, located inside the tank, to kill the bacteria, and the smell.
Clean Your Pipes
Even if you clean your bathroom sinks regularly, you probably don't clean the inside of your pipes. Unfortunately, a stinky layer of biofilm often forms inside sink pipes where it is constantly exposed to the air in your bathroom. To get rid of this smell, remove the sink stopper or drain assembly and clean the inside of the pipe with a bottle brush and a cleaning solution comprised of two tablespoons of organic bleach and one quart of hot water.
Check Your Vent
Somewhere on your roof you will find a vent pipe extending through the surface that is about 4 inches in diameter. This is the main vent stack that provides air to the drain system and keeps air pressure normalized. If this vent stack gets clogged, it can create unpleasant odors in your bathroom. This occurs because water syphons out of the drain traps and allows sewer gases to enter the home. This pipe can be blocked by ice or clogged by a variety of materials, such as a bird's nest or tree leaves, and you'll need to clear away this debris to eliminate smells. If you're not comfortable cleaning your vent or climbing on the roof to check it, call a plumber for help.
Look for a Broken Toilet Seal
A broken seal between the base of the toilet and the bathroom floor can lead to sewer gases escaping. The seal is made of a wax ring that is compressed between the bottom of the toilet and a flange that anchors into the bathroom's floor and subfloor. Either part of the seal can break if the toilet is not anchored tightly enough. If the seal is broken, you will be able to rock the toilet back and forth. You can repair a broken wax ring or flange yourself if you are comfortable with the procedure. If not, call a plumber.