Mold Under the Kitchen Sink

Why It Happens There

Sink cabinets combine every risk factor: supply line connections, a drain assembly, a garbage disposal, an enclosed unventilated space, and particleboard that absorbs water like a sponge and never fully dries.

Leaks here are usually slow — a weeping supply connection or a hairline crack in a drain tailpiece. Slow leaks are worse than fast ones because nobody notices until the material has been wet for months.

Check These Six Things

When It Is a DIY Job

Small isolated growth on a hard surface, from a leak you have already found and fixed, is often reasonable to handle yourself. Texas does not require a licensed contractor below 25 contiguous square feet.

Ventilate, wear gloves and an N95, clean hard surfaces with detergent and water, and dry thoroughly. Skip the bleach — it does little on porous material and is not necessary on hard surfaces that can be scrubbed.

When It Is Not

Swollen or crumbling particleboard means the material is saturated, not just surface-stained, and it needs to come out rather than be cleaned. Growth extending onto the wall behind the cabinet means it has left the cabinet.

Soft flooring in front of the sink, a musty smell in the adjacent room, or growth reappearing after cleaning all indicate the affected area is larger than the cabinet interior. That is the point to stop and get an assessment.

Prevent the Repeat

Put a leak detector puck under the sink — they cost very little and catch slow leaks months earlier than you would. Replace particleboard cabinet bottoms with a sealed or plastic liner. Check connections when you change the trash bag; it takes five seconds.