Does Black Light Actually Work to Find Cat Pee Stains?

Yes, a good blacklight can easily spot invisible cat urine stains (also dog, human, and most other dried urine).

It works because when urine dries, it crystallizes (due to the urea component), and it’s those crystals that glow in UV light.

This article describes how to discover hidden cat pee using a black light.

If you want to safely find and neutralize cat urine smell, we recommend:

How to Use a Black Light to Find Cat Urine

Step 1: Wait until sunset, and turn off the lights in the room. The darker it is, the easier it will be to spot urine stains.

Step 2: Shine your black light about two feet from the floor, and scan around “suspicious” areas, such as corners of the room, and anywhere that smells. We like to use this cat urine black light because it’s made for finding cat pee.

Step 3: Once you find cat pee, mark the location by placing something on it, or sprinkling some baking soda on the spot. Then you know exactly where to treat with a cat urine remover product such as Pee-Off enzymatic cleaner.


Finding Cat Urine with Blacklight Video

This video shows the entire process of finding cat pee with a black light:

Are Black Lights Safe?

Most black lights (also called UV light) you can buy to find cat pee are very low power. The use an LED light, which does not get hot, and is not bright enough to cause harm to people or animals. Like any light, avoid starting straight into it, or shining it into the eyes of any animal.

You’ve probably heard that UV light is dangerous. After all, that’s what sun block is supposed to block, right? But the UV from the sun that can cause cancer and sunburns is higher frequency UV light, and also much more intense. So a low power (battery operated) UV light for cat urine will not cause cancer or give you a sun tan. To be very safe, Harvard Health Publishing recommends that if you shine black light directly onto your skin for long periods, you should consider wearing gloves or sunblock.