Do I need to replace the carpet padding?

If urine has soaked down into the padding underneath your carpet, your job will be more difficult. You may need to remove and replace that portion of the carpet and padding.

Pet Urine in Carpet Padding: How to Tell and What to Do

This guide is about the padding (cushion) under your carpet: how pet urine gets there, signs it has, what cleaning can reach, replacing a section of pad, spill-resistant backings and when to replace the carpet. It uses what the Carpet and Rug Institute (CRI), the IICRC, the AKC, Humane World for Animals, Ohio State University, the City of Long Beach and Shaw Floors say. If a smell returned after you already cleaned, see Pet Urine Smell Came Back After Cleaning: Why and What to Do.

How urine gets into the padding

Humane World for Animals says:

"Your job will be more difficult if urine has soaked down into the padding underneath your carpet."

The CRI's technical bulletin on pet urine describes the path a spill can take when it says some backings "prevent the spillage from penetrating the carpet into the carpet cushion and, perhaps, the subfloor."

Sources: Humane World for Animals, How to Remove Pet Stains and Odors; CRI, Technical Bulletin: Pet Urine and Carpet.

Signs the padding is involved

The smell stays after cleaning

The AKC's answer to "Why does my house still smell after cleaning dog urine?" is: "Urine may have soaked into padding, upholstery, or wood. Repeated treatments or professional cleaning may be necessary." To track down where a smell is coming from, see Why Does My House Smell Like Dog Pee? Finding the Source.

The spot comes back as the carpet dries

The IICRC tip sheet says this about spills in general (that section is about coffee and tea, not urine):

"If the liquid penetrates through to the backing or padding, the dye stain may return after the carpet dries."

A black light shows more than you can see

The IICRC says: "Cleaning professionals use a black/UV light to identify all areas that have urine that can't be seen with the naked eye. Not all urine stains show, so this is the proper way to identify affected areas." Humane World for Animals says: "If you have a black light, use it to identify soiled areas and lightly outline the areas with chalk." The IICRC adds a caution: "It's important to understand that after cleaning, the area may still glow when observed under UV light."

The sources quoted here do not say whether a black light can show how far urine spread in the pad.

Sources: AKC, How to Get Rid of Dog Pee Stains and Smells; IICRC Consumer Floor and Furnishings Care Information (PDF); Humane World for Animals.

What home cleaning can and cannot reach

On reappearing stains after cleaning, the IICRC says:

"Regardless of the method used, carpet cleaning cannot always remove 100% of the soil deeply embedded in the carpet fibers. A certain amount of soil can be left behind at the base of yarns and on the carpet backing."

The CRI says: "Use small hand extractors for quick cleanups of pet accidents, but remember that these quick clean-ups don't take the place of periodic deep cleaning."

For older spots on the surface, see How to Get Old, Dried Pet Urine Stains Out. For a rug you can lift, see How to Get Dog Pee Out of an Area Rug.

Sources: IICRC tip sheet; CRI, Cleaning and Maintenance.

Rinse and extract with a wet-vac

The CRI says: "Don't use a steam cleaner when dealing with urine spots because the heat will set the stain and the smell. Instead, extract the spill with a wet vacuum and rinse with cool water to reduce the odor."

For dried urine on carpet, the AKC says: "Start by rehydrating and extracting the stain." The Long Beach handout explains why an extractor helps:

"To remove all traces of old chemicals and clean old or heavy stains in carpeting, consider renting an extractor or wet-vac from a local hardware store."

"Extracting/wet-vac machines do the best job of forcing clean water through your carpet and then forcing the dirty water back out again. Be sure to follow the instructions carefully."

Whatever cleaner you use, the CRI says "you should still pretest any cleaner on a scrap of carpet or in an out-of-the-way area of your carpet." More carpet steps are in how to get pet urine smell out of carpet on petcleanupkit.com.

Sources: CRI, Cleaning and Maintenance; AKC; City of Long Beach (PDF).

Professional cleaning

The AKC says:

"If odors linger despite repeated cleaning, or if there are multiple or deep stains, professional cleaning may be the best option."

The CRI says: "If necessary, call in a certified carpet cleaning firm that knows how to remove pet stains and odors permanently." The IICRC notes: "If the area still fluoresces after professional cleaning, it does not mean the service provider did an incomplete job removing the urine."

Sources: AKC; CRI, Cleaning and Maintenance; IICRC tip sheet.

Replacing a section of pad and cleaning underneath

Ohio State University's Indoor Pet Initiative says, about cat urine on carpet:

"If the smell is bad and the cat continues to use this area despite all the cleaning, replace the padding underneath and clean the area under the carpet."

The Long Beach handout says: "You may need to remove and replace that portion of the carpet and padding." Humane World for Animals says the same: "In some cases, you may need to replace portions of carpet and padding."

If you buy new pad, the IICRC says: "Always check the carpet manufacturer's specifications or recommendations for padding weight and density before purchasing padding." It warns that "Incorrect padding can actually void the manufacturer's warranty and lead to unwanted wrinkles and ripples."

The sources quoted here do not give steps for cutting out pad or for treating or sealing a subfloor, so ask a flooring installer or an IICRC certified professional how to do that for your floor.

Sources: Ohio State University Indoor Pet Initiative, How to Clean-Up Cat Urine; City of Long Beach (PDF); Humane World for Animals; IICRC tip sheet.

Backings and pads that stop spills

The CRI technical bulletin says:

"Some carpet manufacturers have developed backings that resist spills and even prevent the spillage from penetrating the carpet into the carpet cushion and, perhaps, the subfloor. Check with your carpet dealer about these products."

One example from a carpet maker: Shaw Floors says "Pet Perfect+ styles prevent spills from reaching your subfloor with our innovative LifeGuard Spill-Proof Backing."

Sources: CRI technical bulletin; Shaw Floors, Pet Perfect collections.

When the carpet itself may need replacing

The CRI technical bulletin says:

"When urine spots develop slowly and are noticed after much time has elapsed, the dyes and carpet fibers may be permanently damaged."

"Moisture can weaken the bond between the layers of the carpet, allowing separation or delamination of the backing material to separate."

The IICRC says: "Not only can the dye/color change, but some fibers may become weakened or destroyed as the urine ages and decomposes."

Sources: CRI technical bulletin; IICRC tip sheet.

Stop the repeat visits

The Long Beach handout says: "Even if you can't smell traces of urine, your pet can." See Why Do Dogs and Cats Keep Peeing in the Same Spot? Humane World for Animals says: "If your pet is having regular accidents, have them checked by a veterinarian to rule out medical causes."

Sources: City of Long Beach (PDF); Humane World for Animals.

Using P-Cleaner

P-Cleaner is the Pet Stain & Odor Eliminator Foaming Liquid from Pet Cleanup Kit. The product listing says: "Our rinse-free, water-based formula tackles the toughest stains and odors from urine, feces, vomit, and other organic messes on carpets, rugs, upholstery, and hard surfaces." It also says: "Works on carpets, upholstery, tile, and more.", "No scrubbing necessary" and "Odor-Free & Residue-Free". It is not described for carpet padding or subfloors. Test it on a hidden spot first, as the CRI advises above. Follow the directions on the product label.

Still hunting for spots? The full kit includes a black light.

Buy P-Cleaner on petcleanupkit.com

Quoted from the petcleanupkit.com product listing.