10 Best Mildew Cleaner For Concrete 2025 in the United States

The 30 SECONDS Outdoor Cleaner is a solid choice for anyone looking to tackle stains caused by organic growth like algae, mold, and mildew on various outdoor surfaces. With its easy application method, you simply spray it onto the affected area and rinse it off, making it a user-friendly option for homeowners who may not be familiar with more complex cleaning methods like pressure washing. The cleaner is effective on a wide range of surfaces including concrete sidewalks, wood decks, and vinyl siding, making it quite versatile for different cleaning needs.

One of the standout features is its safety profile; when used as directed, it is safe for lawns and plants, which is a significant advantage for environmentally conscious users. This means you can clean without worrying about harming your garden or landscaping, making it suitable for those with outdoor spaces.

There are a few drawbacks to consider. While the product is efficient at tackling stains, the effectiveness may vary depending on the severity of the mold and mildew. For particularly stubborn stains, you might need to apply it multiple times or even resort to more aggressive cleaning methods. Additionally, the hose end sprayer can sometimes clog, which may complicate the cleaning process.

Wet & Forget Outdoor Moss, Mold, Mildew, & Algae Stain Remover offers a straightforward solution for those dealing with mildew and other stains on concrete and various surfaces. The product's active ingredient is designed to remove green and black stains caused by moss, mold, mildew, and algae without the need for scrubbing or rinsing, which makes it convenient for users who prefer minimal labor. The high-capacity trigger sprayer facilitates easy application on small surfaces.

To use, simply spray it on a dry surface during a cool day and let natural elements like wind and rain clean the stains over time. Green stains can start disappearing within 1-2 weeks, while black or stubborn stains might take several months, and long-established stains could take up to a year to clean fully. This cleaner is non-acidic and bleach-free, making it safer for use around plants, though it's still recommended to flush plants with water before and after application to prevent potential damage.

Wet & Forget's environmental impact is mitigated by its non-toxic formula, but caution is advised to keep it away from bodies of water. Each 64-ounce bottle has an unlimited shelf life and treats about 60-180 square feet, depending on the surface's porosity and level of staining. A notable strength is its simplicity in application and its ability to work over time without the need for manual labor. However, one drawback is the extended time needed for complete stain removal on more stubborn or older stains, which might not suit those seeking quick results.

The RMR-86 Instant Mold and Mildew Stain Remover Spray is designed to tackle stubborn mold and mildew stains, making it a great option for homeowners dealing with these issues on various surfaces. One of its standout features is the fast-acting formula, which works instantly to target deep stains without the need for scrubbing, saving you time and effort. This feature makes it particularly appealing for those who want a quick solution to cleaning challenges.

Additionally, the spray is safe to use on a wide range of surfaces, including concrete, wood, vinyl siding, and more, making it versatile for different cleaning tasks around the home. However, it's essential to consider the safety precautions mentioned for using RMR-86. Proper ventilation and personal protective equipment (PPE) are necessary during application, which might be a drawback for some users who prefer a more straightforward, hassle-free cleaning product.

The RMR-86 is a powerful mildew cleaner that excels in quick stain removal and is suitable for multiple surfaces. Just be prepared to take the necessary safety measures while using it. It’s a solid choice for anyone looking to combat mold and mildew stains effectively, but those sensitive to chemicals may want to explore alternatives or ensure proper safety practices are followed.