24 December, 2025

How to Clean Grout in the Shower: Step-by-Step Cleaning Guide

Clean shower grout like a pro: Remove black mould with baking soda/vinegar or oxygen bleach. Easy steps & daily habits to prevent mildew and keep tiles bright! 

Jaxon Harris
5 mins read
Walk-in shower entrance with mosaic tile floor, stainless steel drain, glass door, and bath mat.

Black grime creeping along shower grout lines can make a bathroom feel dirty, even when everything else looks clean. Grout stays damp for long periods, and poor airflow plus soap residue create the right conditions for mold and mildew to grow. Over time, the grout darkens, looks unhygienic, and can become harder to fix if ignored.
In this blog, we will share effective ways on how to clean grout in the shower. We also cover simple steps to dry the area, improve airflow, and stop mold from coming back, so we can keep grout looking bright. Read on!

Clean grout in the shower

What Makes Shower Grout Turn Black?

Shower grout can turn black for several common reasons, most of which are related to moisture and daily bathroom use:

  • Mold and mildew growth: Grout is porous and easily absorbs moisture. In damp, poorly ventilated showers, mold and mildew thrive and can turn grout black within weeks.
  • Soap scum and body oil buildup: Residues from soap, shampoo, conditioner, and body oils accumulate on grout lines, creating a nutrient-rich surface for mold.
  • Hard water mineral deposits: Calcium and magnesium from hard water can leave deposits that darken grout over time and make it easier for dirt and mold to cling.
  • Everyday dirt and airborne spores: Dust, skin cells, and mold spores in the air settle into grout, especially in frequently used showers.
  • Occasional non-mold stains: Less commonly, hair dye, ink, or cleaning product residue can stain grout black and resemble mold.

Tools and Materials You'll Need to Clean Shower Grout

Before you start cleaning, prepare the following tools and materials to ensure the process is effective and safe:

Protective gear

  • Rubber gloves to protect your hands from chemicals and grime
  • Safety goggles to prevent splashes from irritating your eyes
  • Face mask, especially when using stronger cleaners in enclosed shower spaces

Cleaning tools

  • Stiff-bristled nylon brush or an old toothbrush for narrow grout lines
  • Spray bottle for applying cleaning solutions evenly
  • Bucket for mixing cleaning agents
  • Sponge or soft cloth for wiping away residue
  • Squeegee for drying grout and tiles after cleaning

Cleaning materials

  • Warm water
  • White vinegar (approximately 500 ml)
  • Baking soda (around 200 g)
  • Fresh lemons or lemon juice
  • 3% hydrogen peroxide (500 ml bottle
  • Oxygen bleach or chlorine bleach (diluted according to instructions; never mix with other chemicals)

Bathroom products

How to Clean Shower Grout

Cleaning shower grout doesn't have to be daunting when there’s a clear order to follow. Start by ventilating the area and wearing protective gear. Remove surface dirt from tiles with a damp cloth before focusing on grout. 

Method 1. With Warm Water and a Brush

Fill a bucket with warm water (about 40-50°C) and dip a stiff-bristled brush into it. Scrub the grout lines in circular motions to loosen dirt and soap scum. For better results, let the water sit on the grout for 5-10 minutes to soften residues.
If stains persist, use a steam cleaner with a pointed nozzle to blast away grime. Rinse with clean water and dry thoroughly with a towel or squeegee. 

Method 2. With White Vinegar or Lemon

White vinegar and lemon both work because they are acidic, which helps break down mineral buildup and tackle mold. For vinegar, mix equal parts white vinegar and warm water in a spray bottle (for example, 250ml of each). Spray the grout until fully wet and leave it for 10–15 minutes.
For lemon, squeeze fresh lemon juice directly onto the grout or apply it with a sponge. Let it sit for about 10 minutes, then scrub with a brush. Rinse well after scrubbing, focusing on any blackened areas.

Method 3. With Baking Soda

Baking soda acts as a mild abrasive for tougher stains. Create a paste by mixing 3 parts baking soda with 1 part water (e.g., 150g baking soda and 50ml water) until thick. Apply the paste to grout lines using a toothbrush, pressing it in. Let it sit for 15-30 minutes to draw out dirt.
For extra efficacy, spray the pasted areas with the vinegar solution from the previous method—the reaction creates bubbles that lift grime. Scrub in circles, rinse with warm water, and wipe dry. 

Method 4. With Hydrogen Peroxide

For stubborn mold, make a paste with baking soda (1/2 cup) and peroxide (1/4 cup), apply, wait 5 minutes, scrub with a stiff brush, reapplying if the solution dries. Rinse thoroughly and dry. This is safer than bleach for colored grout and effectively tackles black mold in showers. Dispose of leftovers properly to avoid reactions.

Method 5. With Bleach

Bleach is best kept for the worst cases, and mainly for white grout, because it’s very strong. A safer option is oxygen bleach. Mix it the way the package says (for example, 1/4 cup powder in 1 liter water). Put it on the grout, wait 15–30 minutes, scrub, then rinse a few times so no residue stays behind.
If using chlorine bleach, dilute 1 part bleach to 10 parts water. Spray it on, wait about 10 minutes, scrub, and rinse really well. Keep the area ventilated and wear protection so it doesn’t irritate skin. Bleach can whiten grout well, but using it too often can slowly damage grout over time.

How to Prevent Mold and Keep Shower Grout Looking New?

Clean-looking shower grout needs less moisture and a bit of regular care. A simple routine helps keep grime from sinking into the grout.

  1. Improve ventilation: Use an exhaust fan during showers and keep it on for at least 30 minutes after to lower humidity. In windowless bathrooms, leave the door open or use a dehumidifier to dry the air faster.
  2. Squeegee after each shower: Run a squeegee over the walls to remove water. Less water left behind means fewer places for mold to grow.
  3. Weekly vinegar spray: Spray grout with a 1:1 vinegar and water mix once a week, then wipe. Vinegar helps slow mold spores and reduces early buildup.
  4. Seal the grout every 6–12 months: Apply a quality sealer after cleaning, then let it cure for 24 hours. Sealer creates a water-repellent barrier, so moisture and grime don’t soak in easily.

Conclusion

Learning how to clean grout in the shower helps a bathroom look bright again and deal with black grout causes like mold. Simple methods work well, from vinegar for regular buildup to bleach for tougher stains. With the right steps, grout can look cleaner, and the shower can feel more hygienic without a lot of fuss.
Regular care keeps problems from coming back. Less moisture is good for grout as well as bathroom products, so keep airflow moving and dry the area after showers. A steady routine helps stop major buildup, saves time later, and keeps the bathroom looking fresh for longer.

FAQs

How often should you clean grout in the shower?

You should clean grout in the shower at least once a week for light maintenance to prevent the buildup of soap scum and moisture that leads to mold. In humid Australian climates, deep clean monthly using methods like vinegar or baking soda to address any early discoloration.

This frequency helps maintain whiteness and avoids the need for intensive scrubbing later. Factors like family size and shower usage may require more frequent attention. Consistent habits ensure longevity and hygiene.

Can you put new grout on top of old grout?

Yes, new grout can go over old grout, but only when the old grout is still solid. If the old grout is dirty, cracked, or has mold, the new grout often won’t stick well and can fail later. In showers, that can quickly turn into more cracking or mold.

For a top-up, clean the grout lines well and roughen the surface with a vinegar solution or a grout remover so the new grout can grip. Press on a thin layer with a grout float, around 3–5mm thick, then seal it. For the best shower result, remove the old grout with a grout saw first.

Does vinegar and baking soda damage grout?

Vinegar and baking soda are generally safe for grout and won't cause significant damage when used properly, as they're mild and natural. The fizzing reaction helps lift dirt without eroding the material, especially on sealed grout.

However, excessive use of vinegar on unsealed or porous grout might lead to minor weakening over time due to acidity. Always rinse thoroughly and avoid leaving the mixture on for extended periods.

Do grout pens really work?

Yes, grout pens can work for small stains and uneven color. They cover the marks with color, so grout lines look cleaner fast. They don’t remove the cause, so results depend on how clean the grout is first.

Scrub the grout, rinse well, and let it dry fully before using the pen. For showers, choose a waterproof, mold-resistant pen and seal the grout. The color can last 1–2 years, but deep mold may show through again.

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Jaxon Harris

    Omar Editor

    Jaxon, an Australia interior design enthusiast and bathroom specialist with a passion for creating spa-like retreats in everyday homes. With over a decade of experience in luxury bathroom installations and product development, Jaxon combines technical expertise with an approachable, friendly voice that makes even complex renovation projects feel achievable. From detailed product comparisons and installation guides to elegant styling tips and budget-friendly makeovers, Jaxon is your trusted guide to building the bathroom of your dreams—one thoughtful detail at a time.

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