Last updated: July 21, 2026
Bathrooms are small, but they’re the most water- and code-sensitive room in the house — which makes mistakes expensive. After hundreds of bathrooms across Montgomery County, here’s our honest list of what not to do in a bathroom remodel.
What Not to Do in a Bathroom Remodel
1. Don’t skip waterproofing behind the tile
Tile and grout are not waterproof. Without a proper membrane behind the shower, water rots the wall and you’re re-doing it in a few years. This is the #1 hidden mistake.
2. Don’t undersize the exhaust fan
Poor ventilation causes mold and peeling paint. Size the fan to the room and vent it outside — not into the attic.
3. Don’t move plumbing unless you must
Relocating a toilet or shower drain can add $1,500–$4,000. Keep fixtures where they are when the layout works.
4. Don’t skip the permit
Moving plumbing or electrical requires a Montgomery County permit. Skipping it causes problems at resale. (See remodeling permits.)
5. Don’t buy the cheapest fixtures
Bargain faucets and valves fail fast in a room used every day. Spend on the working parts; save on decor.
6. Don’t forget storage and lighting
Plan a vanity, recessed niche, and layered lighting early — adding them later means opening walls twice.
7. Don’t ignore aging-in-place if you’ll stay long-term
Blocking for future grab bars and a curbless shower costs little now and adds real value later.
8. Don’t change your mind mid-build
Every change order after demo costs time and money. Finalize tile, fixtures, and layout before work begins.
What to Do Instead
Waterproof properly, vent correctly, keep plumbing where it is, pull the permit, and finalize selections up front. See how we run each project on our bathroom remodeling services page, or check real numbers on the bathroom remodel cost guide.
Frequently Asked Questions
What is the biggest mistake in a bathroom remodel?
Skipping proper waterproofing behind the shower tile. Tile and grout are not waterproof, and without a membrane the wall rots within a few years.
Do I need a permit to remodel a bathroom in Montgomery County?
Yes, if you move plumbing or electrical or change the layout. A licensed contractor will confirm and pull the permit.
Should I move the toilet or shower to improve the layout?
Only if necessary. Relocating plumbing can add $1,500-$4,000. Keep fixtures in place when the existing layout works.
Watch: Bathroom Trends to Avoid
Related: See our full breakdown of bathroom remodel cost in Maryland.