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.
If you’re dealing with a fresh urine stain, first soak up as much of the urine with paper towels. Use a blotting technique and don’t press so hard that you drive the urine deeper in the carpet or upholstery.
The product to use for cleaning urine stains is one that states it not only removes the stain but neutralizes the urine odor. Ordinary household cleaners or rug cleaning products won’t do that. It has to be a product specifically made for pet urine. Additionally, don’t use any products containing ammonia because urine contains ammonia and the smell could just trigger a cat to return to that spot to urinate again.