How to Clean Grout Stains & Remove Mold Stains

Person cleaning floor tile grout.

Follow these grout cleaning tips and directions for removing mold stains to refresh your bathroom grout with the power of bleach.

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Floor tile grout gets dirty from trapped dirt, spills and moisture that seep into its porous surface. In damp areas like bathrooms, lingering moisture creates the perfect environment for mold stains and mildew stains to grow in the grout lines. Without regular cleaning, buildup can become deeply embedded.

How often should I clean grout to prevent mold?

Grout should be cleaned every one to two weeks to keep it bright and prevent dirt and buildup. In moisture-prone areas like bathrooms, more frequent cleaning may be needed, along with regular drying of surfaces.

What should I use to clean & remove mold stains on grout?

How to clean & get rid of mold stains on grout with bleach

  1. Prep the area

    Remove any personal care items, floor mats, and shower curtains. Open a window or door to improve air circulation during cleaning.

    open window ventilation

  2. Mix the bleach solution

    In a bucket, mix 1 gallon of water with 1/3 cup of Clorox™ Disinfecting Bleach. This dilution ratio will help remove mold stains on hard, nonporous surfaces. Wear gloves and clothing that you don’t mind getting splashed.

    Close-up of a white bottle pouring out clear liquid, and stream of water from upper right.

  3. Apply and scrub the solution

    Use a nylon brush to apply the bleach solution to the grout and mold-stained areas. Let the solution sit on mold-stained surface for 10 minutes. Scrub heavily stained areas with the brush to effectively clean mold stains from grout. Alternatively, squeeze Clorox™ Toilet Bowl Cleaner with Bleach directly on grout and let sit for 10 minutes. Scrub heavily stained areas with the brush to effectively clean mold stains from grout.

    Person cleaning floor tile grout.

  4. Rinse and air dry

    Rinse the grout and tiles thoroughly with the showerhead or a bucket of clean water. Allow the area to air dry completely before placing items back in the shower.

    Hand holding a handheld showerhead with water spraying.

Do-it-yourself alternatives to clean grout

If you don’t have bleach on hand, here are some DIY options for cleaning mold stains in grout. But use with caution on surfaces due their acidic or abrasive qualities.

  • Vinegar and water solution: Mix equal parts vinegar and water in a spray bottle and apply to the grout. Let it sit for 10 minutes, then scrub and rinse.

  • Hydrogen peroxide: Apply hydrogen peroxide directly to the grout for a less intense cleaner. Scrub after letting it sit for several minutes.

Tips for how to clean grout with bleach

  • Know the right bleach-to-water ratio: https://www.clorox.com/learn/bleach-dilution-ratio/
  • Use freshly mixed solutions — bleach degrades over time when diluted.
  • Never mix bleach with vinegar, ammonia or any other cleaner — it can create dangerous fumes.
  • Wear gloves and ensure good ventilation during use.

Frequently Asked Questions

Is mold on grout dangerous?

In small amounts, mold on grout is generally not harmful. However, heavy exposure may result in respiratory issues, allergies and other health problems, particularly for those with asthma or weakened immune systems. It's important to remove mold quickly and improve ventilation to prevent further growth.

How to address mold stains in grout?

Regularly clean sealed grout with a Clorox™ Disinfecting Bleach solution as directed. A best practice with grout care is to keep your floors and walls dry by improving ventilation in bathrooms and kitchens. Use an exhaust fan or open windows to reduce humidity. Sealing grout with a high-quality grout sealer can help prevent mold by creating a protective barrier that resists moisture.