How to Clean Grout Between Floor Tiles — From Discoloured to White Again

Floor tile grout is porous cement that absorbs dirt, grease, and bacteria from foot traffic and spills over time. Because it's recessed below the tile surface, mopping passes over it without cleaning it — the mop just redistributes the same dirty water into the grout lines. Over years, light-coloured grout becomes grey or brown. Here's how to restore it.

Start with the Least Aggressive Method

Grout can be lightened or damaged depending on the approach. Start mild and escalate only if needed.

Method 1: Baking Soda and Vinegar (For Light to Moderate Staining)

1. Sprinkle baking soda liberally over the grout lines on a dry floor
2. Spray white vinegar over the baking soda — it will foam as it reacts, which helps lift surface soil
3. Let it work for 5–10 minutes
4. Scrub with a stiff grout brush or old toothbrush along the grout lines — always scrub along the line direction, not across the tiles
5. Rinse with clean water and mop up

Method 2: Baking Soda Paste with Dish Soap (Better Penetration)

Mix baking soda with a small amount of dish soap and enough water to make a thick paste. Apply directly to the grout lines with a brush, let sit 10 minutes, scrub, and rinse. The surfactant in the dish soap helps lift oil and grease that the vinegar method doesn't reach.

Method 3: Oxygen Bleach (OxiClean) — For Heavily Stained Grout

Oxygen bleach is effective, colour-safe, and less damaging than chlorine bleach for most tile and grout.

1. Mix oxygen bleach powder with hot water according to package directions (typically 2 tablespoons per 500ml)
2. Pour or apply with a brush directly onto the grout lines
3. Let sit for 15–30 minutes — the extended dwell time is what does the work
4. Scrub with a grout brush
5. Rinse thoroughly with clean water

Method 4: Chlorine Bleach (For White Grout Only, Last Resort)

Chlorine bleach (diluted 1:3 with water, applied with a brush) is the most powerful option but can discolour coloured grout and damage some tile finishes. Use only on white or near-white grout, in ventilated areas, and rinse completely. Never mix bleach with vinegar or other cleaners.

Grout Brush Selection

The right brush makes a large difference. A purpose-made grout brush (narrow, with stiff bristles) reaches inside the grout line better than a general scrub brush. Electric grout cleaning brushes (cordless drill attachment type) are worth the investment for large areas.

After Cleaning: Seal the Grout

Once the grout is clean and completely dry (allow 24 hours), apply a grout sealer to protect it from future staining. Grout sealer is available at hardware stores and is applied by running the applicator tip along the grout line. This step prevents the deep staining that makes grout require heavy cleaning in the first place. Reseal annually in high-traffic areas.

Grout scrubbing is part of Maidless's deep cleaning service. Book a Toronto deep clean — HST included.