Why Is the Cabinet Under My Kitchen Sink Wet? What to Check Before Replacing It

1. Stop more water reaching the cabinet

Take out stored items if you can do so safely. Stop using the sink while water is still leaking. If you know the right water valve and can reach it safely, close it. Do not force a stuck valve; ask a plumber or your building team for help.

If water is near a plug, socket or water purifier power point, stay clear. Do not touch wet electrical parts. Get the power made safe by the right person before checking the cabinet.

Take a wide photo and a close photo of the wet spot. Note when you first saw it. This helps the plumber see what happened, even if the patch dries before the visit.

2. Note when the water appears

Do not take pipes apart to find the answer. Note what you have already seen, and ask the plumber to check each possible source. These clues help guide a check; they do not prove the cause.

• Wet when the sink is not in use: ask about the water supply connections and any purifier tubes.
• Wet after water drains: ask about the sink waste and drain joints.
• Wet after washing the worktop: ask about the sink rim, tap base and nearby joins.
• Many small drops on a cool pipe: ask whether damp air is making water drops, called condensation.

Further reading: Franke: sink fitting and leak checks · US EPA: moisture, drying and condensation

3. Ask for a pipe check before a woodwork quote

The curved or cup-shaped drain part under the sink is called a trap. It holds some water to help keep drain smells out of the home. Its seals and connections need to fit well.

Ask the plumber to check the supply, sink waste, trap and wall connection. If you have a water purifier, ask for its tubes to be checked too. Keep a record of the part replaced and the bill.

In a flat in Kudasan or Raysan, tell the building team if the wall or floor outside your unit is wet too. Ask whether a shared pipe needs checking before someone opens the wall. A photo alone cannot settle this.

Further reading: hansgrohe India: drain traps and seals

4. Can the old cabinet stay?

Once the source is fixed, have the base, sides, back and door checked. A sound door may stay even if one panel needs replacing. Ask which parts are damaged and which still hold their fittings well.

Swollen edges, loose surface layers or weak screw points need closer care. The carpenter should also check any part supporting the worktop. Do not add heavy pots to a weak base.

Ask for a repair option and a replacement option, with the reason for each. Replacing one panel may need the sink or counter to be moved. Get that work included before comparing the totals.

Further reading: CenturyPly: boards and fitting in wet areas

5. Dry first. Finish later.

Wipe up clean water and leave the safe, empty cabinet open to air. The US EPA advises drying wet materials within 24–48 hours to help prevent mould. This is a reason to act soon, not a promise that every board will dry in two days.

Do not cover a wet base with a new sheet, laminate or paint. Ask the team to confirm it is dry enough before finishing. If there is mould, dirty drain water or a lasting musty smell, ask for suitable clean-up help rather than hiding it.

Further reading: US EPA: moisture, drying and condensation

6. Choose the new panel for a wet area

Ask for the board type, grade and finish in writing. For plywood, discuss BWP, short for boiling water proof, and the stated standard. CenturyPly recommends this grade for sink units, along with sealed edges and good fitting.

The surface colour is only one part of the choice. Discuss how pipe holes and cut edges will be protected. Better board should go with sound plumbing; it is not a reason to leave drips.

Keep room to reach the valves and drain. A small removable tray can hold cleaning bottles without hiding all the joints. Choose parts that the plumber can reach for the next repair.

Further reading: CenturyPly: boards and fitting in wet areas

7. Check the repair before filling the cupboard

Ask the plumber to check the connections with the water on, then while water drains. Franke’s fitting guide uses separate checks for the filled sink and draining water. Your installer should follow the guide for your own sink.

Keep the cabinet clear at first. Look again after normal washing-up and the next day. Save a photo of the dry base. If water returns, report it before adding storage or new finishes.

Read the free repair guide below. It explains repair choices, material notes, a quote example and checks after the work. If you need local help, share those notes and photos with your repair team. Start with the cause, then spend on the parts that need work.

Further reading: Franke: sink fitting and leak checks