How to Inspect Under Sinks
The dark cabinets beneath your sinks can hide slow leaks that silently cause mold, wood rot, and structural damage over months or years. This quick inspection involves clearing out stored items, using a flashlight to examine all pipe connections and the P-trap, feeling for moisture along joints, and checking the cabinet floor for water stains or soft spots. Taking 10 minutes quarterly to peer under your sinks catches small drips before they become major water damage repairs costing thousands of dollars.
Cost to Skip This Task
Risk $500 – $10,000 in repairs
Why It Matters
Small leaks under sinks often go unnoticed for months, causing mold growth, wood rot, and structural damage. Catching a drip early is a $5 fix; ignoring it becomes a $5,000 mold remediation. Check quarterly as a habit—perhaps when paying quarterly bills or at each season change. Inspect immediately if you notice musty odors, see insects congregating, or find items under the sink are damp.
Safety First
- Use a flashlight - dark cabinets hide problems
- If you find mold, do not disturb it - mold spores spread when agitated
What You'll Need
Tools
- Flashlight$10
Supplies
- Paper towels$2
Step-by-Step Instructions
Before You Start
Clear items from under all sinks so you can see the pipes and cabinet floor clearly.
- 1
Remove stored items from under each sink
- 2
Use a flashlight to examine all pipe connections and the P-trap
- 3
Feel along pipes and joints for moisture
Run a dry paper towel along connections - it will show even the smallest drip
- 4
Check the cabinet floor for water stains, warping, or soft spots
- 5
Look for mold or mildew (black/green spots, musty smell)
- 6
Run the faucet and garbage disposal while watching for drips
How to Verify Success
No moisture, stains, or mold found. All connections are dry while water is running. Cabinet floors are solid and unstained.
When to Call a Professional
- Active leak that you cannot tighten by hand (plumber $100-200, repair $50-200)
- Signs of mold growth (especially black mold) (mold remediation $500-3000)
- Corroded or deteriorating pipes (pipe replacement $150-400)
- Soft or damaged cabinet floor from prolonged moisture (cabinet repair/replacement $200-800)
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