How to Clean Bathroom Floor Grout Lines

Why Floor Grout Lines Are the Hardest to Keep Clean

Floor grout lines face more abuse than any other surface in the bathroom. They're walked on, splashed with soapy water, and exposed to constant humidity. Because they're horizontal, dirt and grime settle directly into them rather than running off. Over time, white grout turns gray or black, and mold can take hold. Here's how to get floor grout lines truly clean.

What You'll Need

• Grout cleaner or baking soda
• White vinegar
• Long-handled grout brush
• Spray bottle
• Rubber gloves
• Microfiber cloths or mop
• Steam cleaner (optional)
• Grout sealer (for after cleaning)

Step-by-Step: How to Clean Floor Grout Lines

Step 1: Sweep First

Remove all loose dirt, hair, and debris before applying any liquid cleaner. Wet cleaning over dry debris just creates mud in the grout lines.

Step 2: Apply Grout Cleaner

Apply Zep Plus Grout Foaming Cleaner along all grout lines, or make a paste with baking soda and water. For extra power, spray white vinegar over the baking soda using a spray bottle and let it fizz for 5–10 minutes.

Step 3: Scrub with a Long-Handled Grout Brush

Use a long-handled grout brush to scrub along each grout line. The long handle means you don't have to kneel on the floor. Work in small sections, scrubbing back and forth along the grout channel.

Step 4: Tackle Mold with a Stronger Cleaner

For black or dark grout lines with mold, apply RMR-86 Mold Stain Remover and let it sit for 15–20 minutes before scrubbing. For severe cases, use Scrubbing Bubbles Foaming Bleach Cleaner.

Step 5: Steam Clean for Deep Results

A steam cleaner with a grout attachment is the most effective tool for floor grout lines. The pressurized steam blasts deep into the porous grout, killing bacteria and mold without chemicals.

Step 6: Rinse and Dry

Rinse the floor thoroughly with clean water. Wipe up dirty water with microfiber cloths and allow to air dry with the exhaust fan running.

Seal After Cleaning

Once grout lines are clean and fully dry, apply a grout sealer to protect them from future staining. Floor grout should be sealed every 12 months due to the heavy foot traffic it endures.

Recommended Products

• Foxtrot Living Grout Brush (Long Handle) — essential for floor grout lines
• Zep Plus Grout Foaming Cleaner — penetrating foam for deep grout cleaning
• RMR-86 Mold & Mildew Stain Remover — for black mold in floor grout
• McCulloch MC1385 Steam Cleaner — deepest clean for floor grout
• Grout Sealer (Professional Grade) — protect floor grout after cleaning