How to Clean Mildew From Vinyl Boat Seats

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Things You'll Need

  • Soft-bristled scrub brush

  • Ammonia

  • Water

  • Rags

  • Dish soap

  • Isopropyl alcohol

Keep your vinyl boat seats dry to prevent mildew growth.

Mildew is a fungus that grows in moist environments. It is no wonder that your vinyl boat seats are susceptible to mildew growth. Mildew on vinyl boat seats is unsightly and makes the surface of the seats look unclean. If left untreated, mildew will continue to spread throughout the vinyl. Luckily, you can remove mildew from the seats rather easily.


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Step 1

Rub a soft-bristled scrub brush lightly over the mildewed boat seats. Keep the brush dry to remove loose mildew. Brush off any loosened mildew from the cushions to keep it from spreading.

Step 2

Mix a solution of ammonia and water into a clean bucket. Use 1 tbsp. of ammonia for every ¼ cup of water.

Step 3

Dip the scrub brush into the ammonia mixture. Scrub the vinyl boat seats gently with the brush and ammonia solution to remove as much of the mildew as possible. Rinse out the brush often while scrubbing.


Step 4

Wipe down the seats with a rag and soapy water. Go over the seats with a dry rag to remove any excess moisture.

Step 5

Mix a solution of equal parts isopropyl alcohol and warm water if the mildew spots persist. Scrub the seats with a clean scrub brush dipped into this cleaning solution. Rinse out the scrub brush often while cleaning.

Step 6

Rinse the seats with a rag and soapy water. Dry the seats thoroughly with a clean rag.


A solution of one part chlorine bleach and four parts warm water can also be used to remove mildew from white vinyl boat seats. Scrub the seats with a soft brush and the bleach solution. Rinse and dry thoroughly.

If your seats are colored, use 4 oz. oxygen bleach and 1 gal. warm water for an alternative cleaning method. Apply the solution with a soft scrub brush. Let it sit for 30 minutes before rinsing and drying the seats. Oxygen bleach is safe for colored surfaces.


Never mix bleach and ammonia. The fumes caused by mixing these two ingredients can be fatal.

Rinse off the boat seats thoroughly with a rag and soapy water before switching from one cleaning solution to another.

Wear rubber gloves and protective eye wear when using chlorine bleach or ammonia.