Question: How can I remove pet urine odor? Why are pet accidents smells so hard to remove?
Answer: Pet urine smell is so hard to remove because of two components that make their urine smell as awful as it does: uric acid and urea.
What happens is this: your dog or cat pees on the carpet, and the uric acid seeps into not just the carpet, but also the carpet pad and the subflooring, where it seeps into the pores of the fibers and flooring materials. Then it reverts to its crystal/salt form, which naturally binds with the carpet fibers or flooring materials, where it remains forever. You may soak that carpet with a steam cleaner and remove some of the components of the urine, but the uric acid (which is mighty stinky) remains there. Uric acid is less smelly when dry and more stinky when moist. This is why the room in which your pet had accidents smells better on a dry sunny day than on a rainy day.
What You Can Do
If the accidents have been limited, you can go to your local hardware store and rent a carpet cleaning machine. Before using the carpet cleaner rinse out the bucket and use a natural cleaner, an enzyme-based cleaner, or a combination of water and vinegar instead of the heavy chemical cleansers that are usually used with the carpet cleaner.
Wait until the carpet has completely dried before determining if the odors have been completely removed. Check both during rainy and sunny days; you'll find there's a difference because humidity levels typically affect odors that have permeated into carpet or upholstery. If you did not get to the source of the odor right away and completely remove it, you probably still have pet accident odors.
If the odor is still present, you will have to call a professional. What makes the pet urine smell so difficult to remove is the urine seeps into the padding of the carpet and the floor below it. The bacteria causes the smells binds with the molecules in the carpet fibers, carpet pad fibers, upholstery material fibers or the flooring.
A restoration services professional can completely remove the pet urine smells through the use of professional equipment and cleaners designed to eradicate the odors. This process involves the use of enzyme-based cleaners (which bind uric acid to the enzymes so they can be removed from the affected materials) and antimicrobial agents to kill the bacteria.