10 Best Mildew Cleaner For Concrete 2025 in the United States

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 Moss, Mold, Mildew, & Algae Stain Remover is a liquid concentrate designed for outdoor surfaces, including concrete, wood, roofs, siding, and more. Its main appeal lies in the easy application: you mix it with water, spray on a dry surface, and then simply wait without scrubbing or rinsing. This method is convenient for users who want low-effort maintenance. The product works gradually, with green stains showing improvement in 1-2 weeks, while tougher black stains may take several months, which is important to know if you want quick results. It can keep surfaces cleaner for up to a year, making it a longer-term solution.

Wet & Forget is fragrance-free and safe to use on many materials, reducing concerns about harsh chemicals or strong smells. However, it requires dry weather and temperatures above freezing for application, and the effectiveness depends on natural rain and wind to wash away the dead mildew, which might not suit all climates or urgent cleaning needs. User ratings are positive, averaging 4.6 out of 5 stars, indicating general satisfaction with its performance.

This product is a suitable option for those looking for a no-scrub, multi-surface mildew cleaner with lasting effects, but it may not be ideal if fast or intensive stain removal is required.

The RMR-86 Instant Mold and Mildew Stain Remover Spray is designed to quickly tackle tough mold and mildew stains, making it a strong choice for cleaning concrete surfaces. Its spray application method is user-friendly—simply spray on and no scrubbing is needed, which saves time and effort. The formula works fast to break down deep stains and is safe for a variety of surfaces including concrete, wood, vinyl siding, and brick, which adds to its versatility.

Safety precautions such as proper ventilation and personal protective equipment are advised, indicating it contains potent chemicals that should be handled carefully. While the product is a liquid with a fresh scent, users should be mindful of these safety aspects. Based on user ratings, it is effective at stain removal, especially for indoor use.

RMR-86 is a convenient and professional-strength option for those needing a mildew cleaner for concrete and other common surfaces, balancing ease of use with strong cleaning power, though users should follow safety guidelines closely.