How often should you reseal grout?
Updated July 2026
Reseal cement-based grout once a year in showers and wet areas, and every 2 years on tile floors, with the same test-first honesty as stone: drip water on the grout line, and if it darkens quickly, it's time. The higher-stakes sibling task is caulk: the flexible joints where tile meets tub, and wall meets wall, get recaulked whenever they crack, peel, or grow mold you can't clean. Those corners move, and moving joints are where showers actually leak. (Epoxy grout, increasingly common in newer showers, never needs sealing.)
What changes the interval
| Your situation | Interval | Why |
|---|---|---|
| Shower walls and floor (cement grout) | Seal yearly | Daily soaking wears sealer fastest exactly where leaks cost most |
| Kitchen/bath tile floors | Every 2 years | Foot traffic wears sealer, but exposure is splashes, not soakings |
| Backsplashes and dry-area tile | Every 3–5 years, if at all | Nearly cosmetic: seal for stain resistance, not waterproofing |
| Water drop soaks in and darkens grout fast | Seal now | The test outranks the calendar in both directions |
| Epoxy grout | Never | Non-porous by chemistry; sealing adds nothing |
| Caulk at tub/corner joints cracked or moldy | Recaulk now (don’t seal over it) | Movement joints are the actual leak path in most showers |
The cost of skipping it
What skipping it costs: water finds the wall. Porous, unsealed grout, and especially failed caulk joints, let shower water wick into the backer and framing, where it works silently: first stubborn grout mildew and a musty smell, then loose tiles and soft drywall on the far side of the wall, and at the end of the line a rotted shower surround or pan: $3,000–10,000+ for demo and rebuild, plus mold remediation if it festered. A bottle of penetrating sealer is $15–30; a tube of tub-and-tile caulk is $8. Few tasks in the house have a steeper cost ratio.
How to do it (1–2 hours per bathroom · DIY)
- Test first: drip water along grout lines in the shower’s wet zone: rapid darkening means seal; long beading means re-test next year.
- Clean the grout thoroughly (pH-neutral or alkaline grout cleaner and a stiff brush) and let it dry 24 hours; sealing traps whatever’s underneath, including moisture and mildew.
- Apply penetrating (impregnating) sealer along the lines with an applicator bottle, brush, or pad; wipe excess off tile faces before it hazes.
- Second coat on thirsty grout after 15–30 minutes; respect the cure time (often 24 hours dry) before showering.
- Inspect every caulk joint: if you find cracking, lifting, or ingrained mold, strip it fully, dry the joint, and run fresh 100% silicone or siliconized tub-and-tile caulk. Never caulk over old caulk.
- While you’re in there: check for hollow-sounding or loose tiles and any soft spots at the shower floor edges, early rot evidence worth catching now.
Knowing the interval is the easy half. OnOtto reminds you at the right interval, and it won't let you snooze it into next year. Tasks persist until they're done, and completing the yearly grout check schedules the next one automatically.
Put this on autopilot, free for 30 daysFrequently asked questions
How do I know if my grout is already sealed, or is epoxy?
The water test answers the sealed question: beading = sealed (or epoxy), soaking = unsealed cement grout. Epoxy grout has a slightly plasticky sheen, perfectly uniform color, and won't absorb water ever; it's common in post-2015 professional installs. If water beads indefinitely and the grout looks glassy-smooth, you likely have epoxy and can drop this task entirely.
Grout sealer vs. recaulking: which actually prevents shower leaks?
Caulk, mostly. The plane-change joints (tub-to-tile, corner-to-corner, floor-to-wall) flex with the house and with every shower's heat cycle; rigid grout in those joints cracks, which is why they get flexible caulk instead. Most "my shower leaked into the ceiling below" stories start at a failed caulk joint or a cracked grout line in a movement zone, not at mid-wall grout. Seal the field grout yearly; police the caulk joints constantly.
My grout is stained and crumbly, not just unsealed. Now what?
Crumbling or missing grout is past sealing. Those lines need re-grouting: rake out the failed sections (an oscillating tool or grout saw), re-grout, cure, then seal. It's a weekend DIY per shower or a $300–600 pro job, still an order of magnitude cheaper than the rebuild that follows years of water intrusion.