Because cat urine has an unmistakable odor, you would think that it would be easy to clean up, but if your cat has found some discreet locations to eliminate then you may not be aware of the problem until he has gone back to that spot repeatedly to urinate. By that time, the urine will have soaked through carpeting and gone down to the carpet pad and even beyond. So it’s very important to first locate all the soiled areas so you can do a thorough clean-up.
Locate All Soiled Areas
The easiest way to do this is with a black light. This is a special light that will cause most urine stains to fluoresce (think of those old disco days when the disco had black lights and it would cause white clothing to almost look electric).
Black lights are available at your local pet product store as well as online. They’re inexpensive and an absolute must-have if your cat is eliminating outside of the litter box.
Using the Black Light
In order for the urine to fluoresce you’ll need to darken the room as much as possible. If it’s a very bright room during the day and there’s no way to darken it, wait until evening for best detection ability.
Hold the light a few inches away from the area you’re checking. If you think your cat has been spraying, be sure to check vertical surfaces as well.
Typically, urine spray will be in a thin stream and indiscriminate urination will be in a puddle.
Keep in mind that the black light will cause other stains to fluoresce as well, so not everything you see will necessarily be cat urine. It can fluoresce blood stains, vomit, diarrhea stains, etc. After using the black light for a while, you’ll get more familiar with the typical look of a urine stain.
Mark the Spot
Since the stain will not be visible once you turn the room lights back on, you’ll need to make sure you’ve outlined exactly where you’ll need to clean. I use painter’s tape (not masking tape) to outline the stain because it’s easy to peel off afterward. Don’t just put a piece of tape over the stain – outline it so you’ll be sure to clean the entire spot. If you don’t get up all of the urine then your cat will still be able to detect the odor and may return to that area again.