Unsealed grout in wet areas becomes a breeding ground for mold, mildew, and bacteria. The porous cement-based material absorbs moisture and organic matter, creating ideal conditions for microbial growth. Beyond health concerns, moisture penetration can damage subfloors, cause tiles to loosen, and create structural problems that are expensive to repair. In bathrooms, unsealed grout often develops permanent discoloration that can’t be cleaned away. Kitchen grout faces additional challenges from food particles and grease, which can create persistent odors and unsanitary conditions. Proper sealing prevents these problems and makes routine cleaning much more effective.