What Causes Grout to Get Dirty and Discolored?
Grout is the material used between tiles to fill in gaps and create a uniform surface. Over time, grout can become dirty, dingy and discolored for a few reasons:
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Moisture – Excess moisture from showers, sinks, bathtubs etc. can seep into grout and cause mildew and mold growth, leading to discoloration.
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Soap scum – Soap and shampoo residue can build up in grout over time, leaving behind a dull, dirty film.
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Minerals – Hard water contains minerals like lime, calcium and magnesium that can get deposited in grout. This leaves behind mineral deposits and stains.
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Traffic – Constant foot traffic in high use areas like kitchens and bathrooms can wear down grout over time, causing it to become dirty and stained.
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Sun exposure – Sunlight and UV rays can cause grout to fade or yellow over time.
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Improper cleaning – Using harsh cleaners and scrubbing too aggressively can erode and discolor grout.
Cleaning vs. Regrouting vs. Re-Sealing
There are a few options for refreshing dingy grout:
Cleaning
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This involves using cleaners and scrub brushes to manually clean the grout.
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Best for grout that just needs a deep clean to look new again.
Regrouting
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This involves digging out old grout and reapplying new grout.
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Best for grout that is cracked, crumbling and too far gone to be cleaned.
Re-Sealing
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This involves applying a sealant over existing grout.
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Best for sealing and protecting grout that is in good shape but porous and susceptible to getting dirty again.
Step-by-Step Guide to Cleaning Dirty Grout
If your grout just needs a good cleaning, follow these steps:
1. Prepare the area
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Remove any caulk or sealant from the edges of the tile with a razor. This prevents contamination of the grout.
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Dry the surface completely so it is ready to receive cleaning solutions.
2. Apply cleaner
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Use a specialty grout cleaner or make a paste of baking soda and vinegar.
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Apply it liberally along the grout with a scrub brush or old toothbrush.
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Let it sit for 5-10 minutes.
3. Scrub
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Scrub vigorously to loosen up dirt and stains in the grout.
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Use a grout brush or stiff bristle brush for best results.
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Re-apply cleaner as needed.
4. Rinse
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Rinse the area well with clean water to remove all cleaner residue.
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A shower sprayer helps rinse efficiently.
5. Dry & seal
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Allow area to dry completely, Ideally for 24 hours.
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Apply a grout sealer to protect the grout and prevent future stains.
6. Caulk edges
- Once fully dry, re-caulk edges around the tiles with fresh waterproof caulk.
Tips for Preventing Dirty Grout
Follow these tips to keep grout looking cleaner longer:
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Use a grout sealer to protect grout and make it easier to clean. Re-seal yearly.
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Wipe spills immediately to prevent stains.
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Sweep or vacuum regularly to remove surface dirt.
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Use a squeegee after showering to prevent water pooling.
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Consider re-grouting high traffic areas every 2-3 years. New grout stays cleaner.
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Clean grout with gentle cleaners like dish soap, hydrogen peroxide or vinegar. Avoid harsh chemicals.
With some elbow grease and the right techniques, you can get dingy grout looking fresh and clean again! Proper ongoing care will help keep it that way.



