What's the difference between mold and mildew? Learn how it grows and what homeowners can do to prevent it with the local bathroom remodeling experts at West Shore Home.
Mold and mildew may seem synonymous, but there are small differences between the two. Here’s how to spot the difference, understand what’s driving the growth, and keep both from coming back. And, if your space needs a longer-term fix, West Shore Home can help with low-maintenance, grout-free bath and shower solutions.
Mold vs. Mildew: What’s the Difference?
Mildew (surface fungus)
Look & texture: Flat, powdery, or fluffy film. Common colors: white, light gray, or yellowish.
Where it shows up: On damp surfaces—especially caulk, grout lines, shower curtains, and the corners of walls.
Growth pattern: Spreads across the surface; usually easier to wipe away.
Smell: Light musty odor (or none at all).
Health note: Typically milder; can still irritate those with allergies or asthma.
Mold (deeper, more persistent fungus)
Look & texture: Dark green, brown, or black, often spotty or fuzzy with a raised texture.
Where it shows up: Can penetrate porous materials like drywall, unsealed grout, wood trim, or backing materials behind tile.
Growth pattern: Roots (hyphae) can anchor into materials, making it harder to remove completely.
Smell: Strong, persistent musty odor.
Health note: Some molds can aggravate allergies and respiratory issues; widespread growth should be addressed quickly and safely.
Quick visual rule of thumb: powdery and light = likely mildew; darker, fuzzy, or penetrating = likely mold.
Causes: Why Bathrooms Breed Mold & Mildew
High humidity & poor ventilation (long, hot showers without adequate exhaust)
Frequent condensation on cold walls, mirrors, and window frames
Leaks (dripping valves, loose supply lines, compromised caulk, failed grout)
Porous or cracked surfaces that trap moisture (aged grout, unsealed stone, damaged drywall)
Soap scum & organic residues (a ready food source for fungi)
Clutter & soft goods (loofahs, damp towels, and bath mats that stay wet)
How to Tell Which One You Have
Surface wipe test: If a fresh, light film wipes away easily with a household cleaner, it’s likely mildew. If it stains, returns quickly, or feels raised and fuzzy, it may be mold.
Material check: Growth on painted drywall, raw wood, or behind loose tile often indicates mold that’s taken hold beneath the surface.
Odor & spread: A strong, persistent musty odor and irregular dark spotting suggests mold rather than mildew.
Scope matters: If the affected area is large (for example, multiple square feet), recurring, or you suspect it’s inside walls or ceilings, consider professional assessment and remediation.
Prevention: Keep Moisture Down and Surfaces Clean
Control humidity
Run a vented exhaust fan during showers and for 20–30 minutes after.
Crack a window slightly if possible; use a dehumidifier in persistently damp spaces.
Keep shower doors/curtains open after use to promote airflow.
Eliminate water sources
Fix leaks promptly (shower valve, supply lines, toilet seals).
Re-caulk seams that have gaps or cracks; re-grout or seal grout that’s failing.
Ensure shower walls and pans are properly sloped and sealed to prevent standing water.
Reduce food sources
Rinse & squeegee walls and glass after showers to remove soap film.
Weekly clean with a non-abrasive bathroom cleaner; launder shower curtains/liners regularly.
Hang towels and bath mats to dry completely between uses; avoid overcrowding shelves and corners.
Choose low-maintenance materials
Favor grout-free, non-porous wall systems and solid-surface surrounds over traditional tile and porous stone in high-splash zones.
Use mold-resistant backer boards and high-quality sealants at seams and penetrations.
How West Shore Home Helps Prevent Mold & Mildew
If you’re fighting the same spots over and over, the materials and waterproofing behind your bath or shower may be the problem. West Shore Home offers:
Grout-free, low-maintenance wall systems that don’t trap moisture or soap scum like traditional grout lines
Durable, non-porous surrounds designed to resist staining and make routine cleaning fast and easy
Proper waterproofing and sealing at seams, niches, and fixtures to help prevent moisture intrusion
One-day bath and shower replacements performed by trained employee installers, never subcontractors
Design options (tubs, showers, accessories, grab bars, shelving) to refresh your space and simplify upkeep
Financing options for qualified applicants
When to Call a Professional
The growth keeps returning soon after cleaning
You notice soft drywall, bubbling paint, or loose tile
The area of visible growth is large, or there’s a strong musty odor you can’t source
You’ve had a leak or flood and aren’t sure if the materials behind the wall are dry