Urine Mapping and Dectecting Urine in Carpet

I have been asked by several property management companies if we offer black light urine mapping as part of our services. We do use a black light, but our service is much more then that. Lets examine what a typical urine mapping is, and why I think it’s a practice that is fundamentally flawed, and then a more comprehensive way to detect urine.

Dog and cat pee will  fluoresce or glow under a black light. A typical black light urine mapping is where the lights are turned off, shades are shut and the carpet cleaner will do a tour of the carpet with a sketch of the house in hand and mark down any spots on the carpet that appear to glow.  This can be very useful information, but it is not complete. A map made from black-light data only can be misused information because although urine will  fluoresce, so will many other substances including:

  • Woolite Carpet Cleaning ProductsThings that fluoresce
  • Baby Powder
  • Glue
  • Tonic Water
  • Most Laundry Detergents
  • Petroleum Jelly
  • And Many More

These “Urine Maps”  are sometimes kept on file, and when you move out another Urine map is created. If there are new spots that fluoresce the management company will tell you that you broke the no pets rule and may charge you for replacing the carpet, or other fines associated with having a pet in your apartment.  Even if you never had a pet in your apartment.

Another problem with using black light as the sole tool for detecting urine spots is that it can miss urine. Products made to protect carpet from UV damage from the sun like Solar Shield, will also make it so spots that should fluoresce, will not fluoresce.

Common sense is needed when detecting damage from urine. A black light is a good tool to figure out where to start looking for damage but is in no way a sure sign that urine is present. Urine maps based off of these black light tests seem to give management companies leverage is getting damage money from a renters deposit, but to really determine if there is damage further tests should be performed.

To really detect if damage has been done to a carpet you can use some of the following guidelines:

  • Use a black lite to find possible areas of contamination.
  • Include other areas that don’t fluoresce but may show other signs of Urine contamination.
  • Smell the affected areas
  • Look for physical damage to carpet fibers
  • Look for discoloration and staining of fibers
  • Use a moisture probe or meter to check for Urine in the carpet backing, padding, or subfloor

As urine dries it leaves behind urine crystals and salts which consist of bacteria, urochrome, uric acid, urea, proteins and hormones. Once dry the crystals become more concentrated and the odor more pungent. Simple cleaning will not remove this odor. Urine salts  will draw the moisture from the air and always be a little wet and can be detected by moisture probes years after initially being contaminated.

After contamination is detected, a carpet cleaning technician with experience and training will quickly be able to determine what level of contamination has occurred and will have the tools to be able to help.

If you are being told there is a problem with urine in your carpet and you don’t think that’s the case, give me a call. I’ll take a closer look at what’s really going on.



5 thoughts on “Urine Mapping and Dectecting Urine in Carpet

  1. Clare

    I recently rented an apartment, which I found out after I moved in had previously housed a dog. I can smell the urine in many places. I did use the black light method. The apt did re-clean an area, then came back and used some type of enzyme. But the rest of the apt has many many areas that appear soiled/smell.There is even a spatter on 2 walls but the apt says that must be where they sprayed for bugs. And they state there is no issue, no smell. How can I determine and show them the carpet is ruined and needs to be replaced. Note: this is an expensive “luxury” apt.

    1. Gavin Post author

      That is a tricky issue. Stains are easy, take a picture and it’s obvious that the carpet is either soiled or damaged. But it’s hard to show someone smell. What you can do it prove that there are urine crystals still in the padding of the carpet.

      Buy an inexpensive moisture meter like this one:


      You can now stick the pins into the carpet padding and see if you get a reading. If you have moisture in areas under the carpet, you have found the source of your smelly problem.

      It could be that it wasn’t cleaned and flushed out well enough, or the enzymes didn’t do their job, or you may have a completely different issue going on, but it would still require attention.

      One thing to keep in mind is that enzyme treatments often take a few days to work, and will stay wet for a few days, but then will dry all the way. A heavy urine contamination will never dry as it will continue to pull moisture from the air.

  2. hope

    is woolite the only cleaner that will show up florescent? We are being charged saying we had a pet when we didn’t!!!

    1. Gustavas007 Post author

      Woolite just is one of many cleaners that would show up. You might want to check the cleaners you commonly use as well as laundry products to find the real cause of your glowing spots.

  3. Pingback: Odor from the carpets! - Carpet Care Cleaners

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