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.

The Wet & Forget Outdoor Moss, Mold, Mildew, & Algae Stain Remover is a user-friendly cleaning solution designed specifically for outdoor surfaces, making it an excellent choice for tackling mildew on concrete. One of its standout features is the Xtreme Reach Hose End nozzle, which allows for easy application up to 30 feet away, making it convenient for cleaning hard-to-reach areas like roofs and siding. The product is bleach-free and non-acidic, which is a significant plus for those concerned about environmental safety. Additionally, it’s effective over time, as it cleans with rain and wind, which can be more practical than immediate results for homeowners willing to wait for a thorough clean.

On the downside, the product requires some patience, especially for heavy stains, which can take several months to fully disappear. This might be a drawback for users looking for instant results. Also, applying the cleaner requires specific conditions, such as avoiding hot days and ensuring no rain is forecasted shortly after application, which could limit its usability for some. Its coverage of up to 2,000 square feet is quite generous, but porous surfaces may absorb more product, thus requiring additional applications.

Wet & Forget is ideal for outdoor enthusiasts looking to maintain clean surfaces over time, especially if they're not in a rush for immediate results.

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.