How To Clean Mildew From Grout

A beautifully tiled bathroom can be such a pleasing sight, but nothing blights that experience like mildew growing in the grout between the tiles.

If you have ever found yourself with this problem, I am sure you’ve wondered how to clean mildew from grout.

Cleaning out grout is very easy to do and is an effective way to remove mildew. 

Continue reading down below to learn how to clean mildew from grout.

What You’ll Need

Now that you have all the items you need continue reading below for step-by-step instructions on how to clean mildew from grout.

1. Mix Your Cleaning Solution

In a small bowl, mix white vinegar and baking soda.

I recommend the Calyptus 45% Pure Super Concentrated Vinegar.

It’s super concentrated and will probably be the only vinegar you buy this year because it can dilute and make up to nine gallons of cleaning solution.

You want to attain a paste-like consistency.

Combining the two will create a good cleaning solution to loosen and remove mildew from your grout.

2. Apply Cleaning Solution to Grout

Use an old clean toothbrush and apply the cleaning solution to the grout.

You can use any bristle brush, but the size of a toothbrush is nearly perfect for all widths of grout.

Most bristle brushes will be harder to maneuver in smaller spaces where you can find mildew, such as at corners of tubs. 

3. Scrub the Affected Spot

With the brush, vigorously scrub the grout to pull up the mildew from the grout.

This may take some elbow grease as the mildew may have been there a while. 

You may also consider adding more of the solution and letting the solution sit on the grout to loosen the mildew before using a brush.

4. Spray the Affected Area with Bleach and Water Mix

With bleach diluted by water and placed in a spray container, spray the areas you have just removed the mildew from.

Spraying the bleach water onto the grout will kill any remaining mildew that you might not be able to see or reach. 

Ensure that the area is well ventilated when using the bleach!

5. Preventative Steps

Once a month, using the same diluted bleach, spray the grout to prevent any more mildew from growing.

Spraying bleach water monthly will save you time, so you do not need to utilize the vinegar-baking soda scrub method as frequently.

You can also use bleach pens as a preventative step similar to the bleach water spray.

I recommend the Grout Pen White Tile Paint Marker: Waterproof Tile Grout Colorant and Sealer Pen.

It gets wonderful reviews on Amazon.

You can trace along the grout lines with the bleach pen to attain the same mildew-killing effects as the bleach water spray.

6. Clorox Bleach Gel

If you are still noticing issues or want to try a different method, you can use the Clorox Toilet Bowl Cleaner with Clinging Bleach Gel to address the mildew in your grout. 

Dispense the Clorox Bleach Gel along the grout lines between the tiles.

If you are doing this on a vertical surface, you will want to place some paper towels along the bottom to collect whatever drips down to the bottom.

Let this sit for half an hour to an hour.

You may even leave it overnight if it is a nasty case of mildew in grout.

Again, ensure that area is well ventilated due to the bleach.

7. Scrub the Affected Areas with the Clorox Bleach Gel

Using a bristle brush, scrub the grout and any other areas that have mildew.

Again, this may take some elbow grease, but it will help dislodge any larger pieces of mildew from the grout.

8. Rinse the Affected Area Thoroughly

Using a bucket filled with warm water, rinse the areas that you just cleaned.

This will remove any leftover Clorox that might still be present.

Video Instructions For the Vinegar Method

  • Step 1. :09 — Mix solution
  • Step 2. :20 — Apply to grout
  • Step 3. :25 — Scrub
  • Step 4. :42 — Spray
  • Step 5. 1:00 — Preventative Steps

Video Instructions For the Clorox Bleach Gel Method

  • Step 6: :42 — Clorox Bleach Gel
  • Step 7: 1:10 — Scrub
  • Step 8: 1:46 — Rinse


Why Toilet Bowl Cleaner?

The Clorox toilet bowl cleaner is a good option for grout due to the Clinging Bleach Gel that will stick to the grout and remain to kill and dislodge the mildew.

Many other types of solutions will likely slide down vertical surfaces and not address mildew problems on tile walls. 

Even though it is technically toilet bowl cleaner, bleach does not discriminate on the types of surfaces it will clean and sanitize.

It will still kill the mildew, but the clinging formula enhances its effectiveness. 

Can I Mix Any Of These Cleaning Solutions To Create A More Powerful Mix?

No, do not mix chemicals, as this could create an unhealthy and dangerous solution.

The only ingredients from the steps above that you can safely mix would be baking soda and white vinegar. 

Will Any Of These Cleaning Solutions Harm My Grout?

Yes and no.

Too much of anything will be a bad thing.

If you use these cleaning solutions on unsealed grout, it will likely loosen the grout and weaken it.

When using the cleaning solutions, do so in moderation to avoid this issue. 

Can I Clean Mildew Without Bleach?

Yes, beyond using the baking soda and white vinegar method, you can also use hydrogen peroxide.

It is, like vinegar, a natural cleaning agent and even has anti-fungal properties, which is a must when trying to purge your house of mildew.

Using hydrogen peroxide may also leave less residue after being used, especially if you have any children or pets in the house. 

What If I Have Colored Grout?

If your grout is not white, avoid using bleach, as this may cause the grout to fade.

Try one of the alternative methods to avoid causing discoloration of your colored grout.

How Can I Prevent Mildew?

There are different ways to ensure mildew does not grow in your home.

You can increase ventilation by opening windows and utilizing exhaust fans to remove steam from bathrooms.

You can invest in a dehumidifier to decrease the moisture in the air that will lead to mildew growth. 

Also, preventive steps, such as spraying the grout with a diluted bleach solution or even hydrogen peroxide, may help kill any mildew showing early signs of infestation.