How to Remove Dark Water Spots on Wood Floors

Hardwood floors are very durable and can last for hundreds of years with a minimum of maintenance. Regular sweeping, placing mats in front of any exterior doors and promptly wiping up any spills will keep your floors looking beautiful. Hardwood floors do, however, stain easily if not treated properly. Fortunately, the majority of stains can be treated if you know how. Dark water spots are one of these types of stains.

(Image: Jupiterimages/ Images)

Things You'll Need

  • Fine-grade steel wool

  • Floor cleaner or mineral spirits

  • Household vinegar

  • Very fine-grit sandpaper

  • Floor wax

  • Buffing cloth

  • Oxalic acid (wood bleach)

Step 1

Make sure that the stain was made by water. Pet urine stains can also leave dark marks but need to be handled differently than water stains because of their acidic nature. If in doubt, try the water treatment first.

Step 2

Use floor cleaner and fine-grade steel wool (number 000) to clean the spot and the surrounding area. Mineral spirits are also effective.

Step 3

Place straight household vinegar on the spot for three to four minutes and rinse. That should remove most spots. Re-treat with vinegar a second time if necessary.

Step 4

Sand any spots that remain with very fine-grit sandpaper, going in the direction of the wood grain. Lighten the pressure as you move out to the area surrounding the spot for about three to four inches to blend the sanded area with the rest of the floor. Apply wax and polish with a cloth.

Step 5

Apply oxalic acid (wood bleach) to any further stubborn spots. Use 1 oz. of acid per quart of water and place the mixture directly on the spot. Clean off the acid as directed on the container and buff the area with a cloth.

Step 6

Refinish the floor after treatment if there is an obvious color difference. Without the dark spots, the floor should refinish evenly.


Dark water stains are caused by water or other liquids that are left standing. Standing liquids can also warp the floor and cause cracking. It is important not to wet-mop a hardwood floor and to remove liquid spills promptly by wiping them up from the edges first, moving toward the center.

References & Resources