How to Remove Black Marks Left by Urine on Hardwood Floors

When hardwood flooring turns dark, it’s the unfortunate result of moisture penetrating the wood itself. Although there are a few “quick fixes” proclaimed to work, the only sure way to undo the damage is to restore the floor. Here’s what to do.

• Wood Bleach
• Fine grit sandpaper
• Paint brush
• Eye protection
• Wood finish
• Clean rag

1. Sand the protective finish off the darkened area. Use a fine grit sandpaper to reduce the risk of gouging the wood. It’s not advised to try to sand the dark spot away, as doing so will almost certainly leave a depression in the wood.
2. Use the clean rag to wipe the area free of dust from sanding.
3. Wearing eye protection, use the brush to apply a very thin coat of wood bleach to the stain.
4. Wait a couple of hours before examining the spot. If it’s still darker than the rest of the floor, apply a second coat.
5. Allow 24 hours for the bleach to evaporate and the floor to dry. If you accidentally lighten the floor too much, use a wood stain that matches the floor to restore the color.
6. When the color is right, and the floor is completely dry, apply a protective wood finish. Unless you are refinishing the entire floor, you should opt for the same type of finish that remains on the rest of the hardwood.

• If you don’t have wood bleach, you can substitute regular household bleach or peroxide, but these options may not work as well and might require more treatment for the same result.
• If you have a small spot, consider waiting a few days before treating it. The stain may start to lighten on its own as it dries.
• If dark stains are a frequent problem, consider adding another coat of finish to the floor.