What happens when ammonia from dog urine & bleach are mixed?

Updated April 13, 2018

If your dog urinates inside of your home, you need to clean up the stain to prevent the dog from returning to the spot and remarking it. Although chlorine bleach has antibacterial and antifungal properties, making it a multipurpose cleaner for many types of pet stains, avoid using it to clean dog urine. The urine contains ammonia that reacts with the bleach to form a toxic gas.

Dog Urine

Normal dog urine contains waste products from metabolism including dissolved mineral salts and other compounds, according to VCA Animal Hospitals. A dog excretes these waste products through its kidneys, including a small amount of ammonia. If a dog suffers from a bladder infection, the concentration of ammonia in the urine increases, due to the production of urease. This enzyme breaks down a chemical known as urea in the urine, producing an excess amount of ammonia in the urine.

Chlorine Bleach Reactions

Chlorine bleach contains sodium hypochlorite as the main active ingredient. This chemical kills germs and bleaches fabrics and other surfaces. Normal bleach contains this ingredient in a concentration of 5 to 10 per cent, according to the Clorox Co. When mixed with ammonia, drain cleaners or other acids, sodium hypochlorite reacts to form dangerous gases called chloramines, according to the Washington State Department of Health. Because of the ammonia contained in urine, cleaning urine of any kind, including dog urine, results in noxious fumes due to the production of chloramine gas.


If you spray chlorine bleach on dog urine, the resulting chloramine gases can cause coughing, shortness of breath, wheezing, nausea, watery eyes, irritation to the throat, nose and eyes, and pneumonia according to the Washington State Department of Health. Adding a greater amount of bleach, such as a cleaner, to a lesser amount of ammonia, such as the small amount present in dog urine, can produce an explosive, volatile compound called nitrogen trichloride, according to the City of Ravenna Department of Health.


To clean dog urine, absorb as much of the urine as you can with a cloth or paper towels. Rinse the area with water and saturate it with an enzymatic cleaner to break down and remove the chemicals in the urine. To sanitise the area after this process, use a diluted bleach solution of 1 part bleach to 10 parts water in a well-ventilated area, according to the Centers for Disease Control and Prevention. You can also use ingredients other than chlorine bleach to sanitise the area, such as oxygen bleach or vinegar, which both have antimicrobial properties to kill germs.

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About the Author

Based in Las Vegas, Susan Paretts has been writing since 1998. She writes about many subjects including pets, finances, crafts, food, home improvement, shopping and going green. Her articles, short stories and reviews have appeared on City National Bank's website and on The Noseprint. Paretts holds a Master of Professional Writing from the University of Southern California.