Discoloration in Rugs from Urine and Mold

by Ruth Travis / Rug Lady Seminars

I love pets.  As a “kid” I grew up with dogs, cats, horses, cows, ducks, chickens and even quail.  At one time I was “supporting” thirteen outdoor cats (I’m a sucker for strays), two indoor cats, three dogs and two horses.

I also love rugs.  I owned a rug store for five years and have accumulated quite a few Orientals and other wool and synthetic rugs that cover the hardwood and tile floors in my home. Unfortunately, rugs and pets don’t mix!  No matter how careful I was in keeping my pets out of certain rooms, accidents happened.

The following statistics were compiled from the American Pet Products Manufacturers Association 2009-2010 National Pet Owners Survey.


  • There are approximately 77.5 million owned dogs in the United States
  • Thirty-nine percent of U.S. households own at least one dog
  • Most owners (67 percent) own one dog
  • Twenty-four percent of owners own two dogs
  • Nine percent of owners own three or more dogs
  • On average, owners have almost two dogs (1.7)
  • The proportion of male to female dogs is even
  • On average, dog owners spent $225 on veterinary visits (vaccine, well visits) annually


  • There are approximately 93.6 million owned cats in the United States
  • Thirty-three percent of U.S. households (or 38.2 million) own at least one cat
  • Fifty-six percent of owners own more than one cat
  • On average, owners have two cats (2.45)
  • More female cats are owned than male cats (70 percent vs. 65 percent respectively)
  • Cat owners spent an average of $203 on routine veterinary visits

These stats are good news for the professional cleaner, since animal urine odor, stains and discolorations are reported as one of the most common consumer complaints with textile furnishings.   You can make a lot of money in your cleaning business by becoming a deodorization and decontamination “expert.”  Just keep in mind, however, that dealing with urine problems is never as simple as pet owners thinks or some product manufacturers claim!

Years ago – 1989, I think – Dr. Steve Spivak wrote a classic article entitled “Pet Peeves.”  His insightful comments then are just as true today.

Two things to remember:

1.         Foremost, it’s the pet owner and their “darling” pet that are responsible for damage resulting from pet “accidents.”  Don’t assume the blame when you can’t make your customers’ furnishings look or smell like new!  The stain or discoloration was there to begin with and is purely their fault, not yours.  As a professional cleaner, you can attempt to clean, deodorize or remove spots and stains, and/or recolor the fabric; but if your actions can’t remedy the damage, that’s unfortunate.  It’s the pet that caused the problem, not your effort to improve a difficult or impossible situation.  Cleaners are not responsible for circumstances beyond their control, although many times, pet owner try to shift that responsibility to them.

2.         There are some great products and procedures available for professionals to use for decontaminating and deodorizing, but remember there is NO magic one-step treatment or product that you or your customer can use to completely eliminate pet stains or odor.  When the fabric has been stained or discolored from the pet urine, it takes a lot of time and effort to attempt to reverse the damage.

Why? . . Because urine components have the ability to stain (dye) and/or bleach (discolor) fibers, especially fibers like nylon or wool.  Don’t forget, when theses fibers are manufactured they are contact-dyed with acid dyes.  When urine, feces or vomit are first excreted from the body, they are highly acidic, just like the dye solution used to fix color on nylon and wool fiber.  If customers act quickly, removing urine’s yellowish stain can be accomplished with almost any cool, neutral detergent solution.  If they don’t act quickly – and who has time to follow their animal around all day – then more complex oxidizers and professional techniques usually are required to remove the stain.   Keep in mind also that the color of the stain can be affected by the age of the animal, the amount of water, and food or medications it has ingested.

Further, if the contaminating substance has not been diluted, neutralized and extracted quickly, then as bacteria in the urine multiplies and produces enzymes, the deposit becomes highly alkaline (smells like ammonia, doesn’t it?), and actually “bleaches” color from fibers.  It’s the ammonia that causes the loss of color in rugs, not necessarily the presence of the yellow pigment in the urine itself.  The loss of dyes caused by prolonged exposure to ammonia is another story entirely. Don’t make the mistake of thinking that the yellow color can be removed with a simple cleaning solution.  Correcting color loss caused by alkalinity can only be accomplished by adding color or spot dyeing fibers.

O.K.  So how to we solve the customer’s problem?  First, you must locate all areas of discoloration.  Discolorations from animal urine may show up readily under high‑intensity inspection lights.  Black (ultraviolet) lights also may be used quite effectively.  Ultraviolet light causes urine salts to “fluoresce” and glow brightly.  Their major drawback is that the room you’re inspecting must be fairly dark.  To avoid having to inspect for urine exclusively after dark, close the draperies or blinds, or alternatively, invest in some black plastic sheeting that you can tape temporarily to the customer’s window or door frame.  Remember, too, that if the customer has been using household spotters, like Resolve®, optical brightener residues that these products leave behind may be mistaken for extensive animal urine damage.  Urine usually reflects a yellow or yellow-green color, whereas optical brighteners glow white or blue-white.

Once you’ve pinpointed the areas of concern, it’s time to begin the decontamination process.  Here’s the step-by-step color restoration procedure I teach in my Color Repair class:

1.      Thoroughly clean affected areas on the rug both front and back.  Then, flush spots completely with water.  I highly recommend that you use a “Water Claw®” spotting tool to extract as much moisture and contaminant as possible.

2.      Ensure that the urine spots have been properly neutralized with an acid spotter.

3.      Rinse again.  A mild oxidizing bleach may be required to remove residual yellowing from the urine deposit.  Be careful working on natural fibers!  There are products available that have been specially formulated for wool and silk.

4.      Check pH of the affected area to ensure that it is between 4 and 7 for nylon or wool rugs.

5.      Adjust your dye bath to between 2-3 in pH; then, evaluate the amount of color loss or gain.

6.      Find the missing primary color or colors to determine what color is required in the dyeing process.  Make the appropriate dye bath by mixing dyes in concentrate and then adding them to several ounces of hot water a little at a time until the desired shade of color is reached.

7.      Apply missing colors one at a time, using either an eye dropper or an air brush.  Start in the center of the color-loss area and apply the dye sparingly in a circular motion.

8.      Ensure that dyes penetrate all the way to the primary backing.

9.      Feather dye into the area surrounding the color repair spot and blend the color into the outer perimeter of the spot.  Start light and deepen the color as needed.  Don’t over-apply color to avoid a dark ring.

10.  Apply any toning dyes or finishing dyes after the missing primary color(s) has been replaced to dull the color to the proper level of intensity.

11.  After the dye repair is performed, use a groomer to align carpet yarns.

Now that you’ve cleaned, neutralized and repaired the discoloration in the rug, there’s a very important basic fact that you and especially your customer must understand.  It con­cerns the territorial nature of animals.  If animals are present, urine will be present.  It is very likely that the animals will return (even after deodorization and recoloration) to remark their territory!  It’s simply part of their psychological makeup.  If the animal smells his peculiar scent, he’s happy; otherwise, he’s not.  Never guarantee urine stain removal, discoloration correction or odor removal if the animal is still present in the home!

Now let’s discuss discoloration from mold.  Since mold is not water soluble, it may create a stain in carpet that may be bleached safely with hydrogen peroxide.  Just like urine, the bacteria that feeds on the waste products of mold off-gases ammonia.  Ammonia can remove color from carpet or rugs, causing a discoloration that requires re-dyeing.  The steps for repairing the discoloration are basically the same as for urine or feces.  However, keep in mind that the mold may have “digested” the rug’s cotton or wool fibers causing permanent damage.  In this case, the only solution is to repair or reweave the damaged area.

So, are you ready to tackle color correction for rugs?  Not as easy as it seems, is it?  Before you jump into this lucrative add-on service, I would highly recommend you get more intense training at an IICRC-approved certification class . . . specifically, Rug Cleaning, Odor Control and Color Repair Technician.

[Ruth Travis is a 25-year veteran of the cleaning and restoration industry.  She has served as an industry volunteer in many capacities, including as President of the SCRT and the IICRC.  She is an IICRC-approved instructor in color repair and rug cleaning.  She currently serves as the WoolSafe® Director for North America (www.woolsafe.org/usa) For more information go to:  www.rugladyseminars.com.]