Discolored grout drags down even an expensive tile installation. Once the lines turn gray, brown, or splotchy, no amount of scrubbing brings them fully back. The fix is not regrouting, which is destructive and expensive, but staining the existing grout to restore or change the color. Staining grout with a quality colorant such as Polyblend Grout Renew, Mapei Grout Refresh, or Aqua Mix Grout Colorant takes a tile floor or shower from dingy to new in about a day, costs under $100 for an average bathroom, and lasts 7 to 15 years before fading.
Part of our Tile & Grout guide — explore the full guide →
What Grout Stain Actually Is
Grout stain is a water-based acrylic pigment system that bonds chemically with cementitious grout. It is not a paint, not a topical coating, and not a sealer in the conventional sense. The polymer penetrates the porous surface of the grout and locks in the color with the same molecules that make latex paint stick to drywall, then forms a thin sealing layer on top. Once cured, it resists water, mildew, and most household chemicals. It does not adhere to epoxy grout, which is non-porous, so always identify your grout type before buying product.
To test grout type, drip a few drops of water on the grout line. Cementitious grout darkens within seconds as it absorbs water. Epoxy grout beads water on the surface with no darkening. Stain works on the former, not the latter.
Color Options and Brand Picks
The major manufacturers offer 30 to 60 color choices, with the most popular shades being warm bright white, oyster gray, mocha, espresso, and charcoal. Top products:
- Polyblend Grout Renew (Custom Building Products): $15 to $22 per 8 oz bottle. Most widely stocked, 40+ colors, available at Home Depot and Lowe’s.
- Mapei Grout Refresh: $18 to $25 per 8 oz bottle. Slightly thicker formula, better coverage on rough grout.
- Aqua Mix Grout Colorant: $28 to $40 per 8 oz bottle. Pro-grade, used by tile restoration contractors, longer working time.
One 8 oz bottle covers approximately 50 to 75 square feet of standard 12-by-12 tile with 1/8-inch grout lines, or 25 to 35 square feet of mosaic tile with denser grout lines. Buy 25 percent more product than your calculator says; the second coat saves the project on darker colors and chipping repairs.
Cost vs Regrouting
Staining grout is dramatically cheaper than regrouting. A typical 60-square-foot bathroom:
- DIY grout stain: $40 to $90 in product, 4 to 8 hours of labor.
- Professional grout staining service: $300 to $700 for the same bathroom.
- DIY regrout (manual removal): $80 to $150 in materials, 12 to 24 hours of labor, risk of cracked tile.
- Professional regrout: $1,200 to $3,500 depending on tile age and removal difficulty.
- Full tile replacement: $4,000 to $12,000+ for the same bathroom.
Stain works for any cement grout in sound condition. If 20 percent or more of the grout is cracked, missing, or crumbling, regrouting is the right call.
Prep Work That Determines Success
Bad prep is why DIY grout staining sometimes peels within months. The grout must be clean, dry, and free of any existing sealer film. Steps:
- Deep clean: Scrub all grout lines with a stiff nylon brush and an oxygen-bleach grout cleaner like Grout-Eez or Stanley Steemer Oxy Boost. Avoid wire brushes, which damage grout.
- Rinse with clean water twice, picking up residue with a microfiber cloth.
- Strip any existing sealer: If the grout was previously sealed within the last three years, apply a sealer remover such as Aqua Mix Sealer & Coating Remover and rinse thoroughly.
- Dry for 24 to 48 hours. Moisture in the grout dilutes the stain and prevents proper bonding.
Test the prep with the water-drop method. If water absorbs within a few seconds across all grout lines, the grout is open and ready for stain.
Application Step by Step
Work in 10- to 20-square-foot sections to control dry time. The process:
- Shake the stain bottle for 60 seconds.
- Apply with the included applicator brush, a fine artist’s brush, or a small toothbrush. Push the stain into the grout, not just over it.
- Wait 30 to 90 seconds for the stain to penetrate.
- Wipe excess stain off the tile face with a damp microfiber cloth, working diagonally across the grout lines to avoid pulling stain back out.
- Allow to dry 60 minutes, then apply a second coat for full opacity, especially on warm white and other light colors.
For glazed ceramic tile, the stain wipes off cleanly. For natural stone and unglazed porcelain, mask the tile face with painter’s tape to prevent staining the tile itself. Plan an extra hour for the masking, but it saves the surface.
Dry Time and First Use
Allow 24 hours before light foot traffic, 48 hours before shower use, and 72 hours before any heavy cleaning. The bond cures fully at 7 days, after which the stain handles standard pH-neutral floor cleaners (Bona, Method, Mrs. Meyer’s) without issue. Avoid acidic cleaners and bleach for the first 30 days while the cure completes.
Color Change Strategy
Light grout to dark is easy; the dark pigment fully covers in one or two coats. Dark grout to light is harder. For example, going from charcoal grout to warm bright white usually requires three coats and may never fully reach the target color because residual dark pigment shows through. For dramatic lightening, regrouting may be the better path.
Color matching to a specific tile or design needs a sample swatch. Buy a single 8 oz bottle in the target color, test in a closet or under the toilet, and live with it for a few days before committing the full bottle to a high-visibility area.
Longevity and Maintenance
Properly applied grout stain lasts 7 to 15 years on bathroom floors and showers, longer on kitchen and entry tile that does not see daily water exposure. Reapply spot touches every two to three years on high-traffic grout lines. Use a pH-neutral cleaner for routine maintenance; harsh bleach and abrasive scrubbing pads will erode the stain.
If the stain looks tired after a decade, the same product simply applies over the existing color with a single coat to refresh.
When to Skip Staining
Staining grout is the wrong choice in three situations. First, if the grout is structurally damaged — cracked, missing chunks, or pulling away from tile edges. Second, if mold or mildew has penetrated below the surface, since stain seals contamination in rather than killing it. Third, on epoxy grout, which the stain cannot bond to. In these cases, regrouting or full replacement is the right path forward.
