10 Best Composite Deck Cleaners 2025 in the United States

The Wet & Forget Outdoor Moss, Mold, Mildew, & Algae Stain Remover is a versatile cleaner designed for multi-surface use, including composite decks. One of its main strengths is the new and improved nozzle, which attaches to a garden hose and offers two spray options: a jet tip for targeting specific stains up to 30 feet away and a fan tip for quicker applications on larger surfaces like decks. This makes it user-friendly for various outdoor cleaning tasks.

The product's bleach-free and non-acidic formula enhances safety, making it less harmful to plants and safe for use around the home, provided you follow guidelines to avoid contact with water bodies and rinse nearby plants before and after use. Furthermore, it has an impressive coverage area, treating up to 2,000 square feet per bottle, which is cost-effective for larger cleaning projects.

This cleaner works over time with natural elements like wind and rain, with green stains typically clearing up in 1-2 weeks, while more stubborn stains may take several months. This delayed result might be a downside for those seeking immediate cleaning effects. It also leaves no residue, which is beneficial for maintaining the appearance of your surfaces. However, the requirement to apply the product on dry days with temperatures above 55° F and no rain forecasted within 4-5 hours could limit its usability during certain seasons. This product is ideal if you seek a hands-off, long-term cleaning approach and prioritize safety and large coverage, but it may not be suitable if you need quick results.

The 30 SECONDS Pro Mold and Mildew Stain Remover is a potent cleaner designed to tackle tough mold and mildew stains on a variety of surfaces, including composite decks. One of its standout features is its impressive cleaning power, boasting a formula that is twice as strong as the standard 30 SECONDS Outdoor Cleaner. This means it can handle the most stubborn stains without the need for scrubbing, saving you both time and effort.

The product is ready to use, which simplifies the application process—just spray it on and watch the stains disappear. Additionally, it works instantly, offering brighter results right away, which is a big plus for those needing quick results. The cleaner is also versatile, suitable for both indoor and outdoor use, covering surfaces like drywall, wood, vinyl siding, concrete floors, and even kitchen and bathroom tiles and grout.

However, there are a few potential drawbacks. While it's effective, its strong formula might pose safety concerns, especially for those with sensitive skin or respiratory conditions, so proper precautions like wearing gloves and masks are advisable. The product is scented, which might be an issue for people sensitive to smells. Moreover, the packaging is quite bulky, with a weight of 36.3 pounds for a 4-pack, which might be cumbersome for some users to handle. Lastly, it’s important to note that while the product claims to leave no residue, ensuring thorough rinsing is necessary to achieve the best results. This cleaner is ideal for those who need a powerful, ready-to-use solution for tough mold and mildew stains on various surfaces, including composite decks.

The Wet & Forget Outdoor Moss, Mold, Mildew, & Algae Stain Remover is an effective composite-deck cleaner that excels in its cleaning power, capable of removing green and black stains without requiring scrubbing, rinsing, or pressure washing. This makes it highly convenient for users looking for hassle-free cleaning solutions. It covers multiple surfaces, including porch steps, headstones, fountains, and even upholstery, showcasing its versatility.

The attached high-capacity trigger sprayer ensures easy application, and the product works over time with natural elements like wind and rain to clean surfaces, which means less effort on the user's part. However, it's important to note that while green stains may clean up relatively quickly (within 1-2 weeks), more stubborn stains can take several months to fully disappear, which might be a drawback for those seeking immediate results. Safety-wise, the product is bleach-free and non-acidic, which is a plus, but users need to be cautious around water bodies and plants, ensuring to spray 100 feet away from lakes, ponds, rivers, and streams and to flush plants with water before and after application to avoid harm.

The product's unlimited shelf life is a significant advantage, and it treats a substantial area of 60 - 180 square feet depending on the stain and surface. While it is unscented, which might appeal to those sensitive to strong smells, users should be aware that it requires application on dry days when rain is not expected within 4-5 hours and when temperatures are above 32°F to avoid rapid evaporation and ensure effectiveness. This product is ideal for homeowners who want a low-maintenance, long-term solution for outdoor cleaning, although patience is required for the best results.