How to Repair Water Damage Under the Kitchen Sink

Water damage under the kitchen sink is a common issue that many homeowners face. Leaky pipes, overflowing sinks, and condensation can all lead to water collecting under the sink, damaging the cabinets and potentially the floor. Left untreated, this water damage allows mold and mildew to grow, causes wood to rot, and leads to a foul odor in the kitchen. The good news is that repairing water damage under a kitchen sink is often a DIY project that can prevent further damage if addressed promptly. This guide will walk through the step-by-step process to assess, clean, dry, disinfect, and restore water damage under the kitchen sink.

What Causes Water Damage Under the Kitchen Sink?

There are a few common causes of water issues under a kitchen sink leading to damage if left untreated:

Leaky Pipes and Plumbing

Cracks or loose joints in the pipes and plumbing can drip water under the sink over time. The constant moisture eventually rots wood, warps cabinets, and leads to mold growth. Kitchen sink pipes also connect to the main water supply for the home, meaning a leak can quickly become major flooding.

Overflowing Sink

If a sink overflows from a clogged drain, leaving the faucet on too long, or a mechanical failure, water spills down the cabinet walls under the sink. Food debris and soap scum exacerbate water damage when sinks overflow.

Condensation Buildup

The enclosed space under a kitchen sink sees a lot of humidity from nearby water sources. As moist air meets the cooler sink cabinet surfaces, it condenses into water droplets that pool below. Even a small amount of condensation over time can mold and rot the cabinets.

How to Repair Water Damage Under the Kitchen Sink

Assessing the Damage Under the Sink

The first step is to assess the extent of the water damage so you can determine the best method for restoration.

  • Carefully remove everything from under the kitchen sink and set items on towels or a plastic tarp to prevent further water damage elsewhere.
  • Check where the water is coming from. Is it an active leak, condensation, or residual standing water? Address the source of the water first.
  • Examine the cabinet interior, walls, floor, and any exposed plumbing for signs of water damage. Look for warping, soft spots, rotting wood, swelling, stains, mold, or mildew.
  • Determine if only the cabinet floor or walls are damaged, or if water has seeped into the subfloor, drywall, or other surrounding areas. Extensive water damage may require professional restoration services.

Drying Out the Area

It’s important to thoroughly dry out the area to prevent further water damage under the sink. Here are three effective methods:

  • Remove any standing water under the sink with a wet/dry vacuum or towels.
  • Use a dehumidifier to reduce moisture in the air and speed up drying time. Keep it running under the sink for 24-48 hours.
  • Place absorbent materials like bath towels, rags, or newspaper under the sink to soak up remaining moisture. Replace damp items regularly.

Make sure to dry all surfaces in and around the sink cabinet, not just visible pools of water. Any remaining moisture can lead to mold, mildew, and rot if left for too long.

Disinfecting and Deodorizing

Even after drying, the area may still smell musty from mold or mildew. It’s important to disinfect all surfaces to inhibit further growth and neutralize odors. Here are some tips:

  • Make a dilute bleach solution of 1 cup bleach per 1 gallon of water. Use this to wipe down the sink cabinet interior walls and floor.
  • Spray or mop white vinegar under and around the sink to help kill mold and bacteria. The acidic vinegar also counteracts musty smells.
  • Apply baking soda and let sit for a few hours before vacuuming up. Baking soda soaks up odors and moisture.
  • Place a bowl of activated charcoal or baking soda in the cabinet to absorb lingering odors. Replace as needed.

Repeat the disinfection process over a few days if smells persist. Address any remaining moisture issues first.

Repairing and Replacing Damaged Areas

  • For stained or scratched cabinet walls, sand down damage and reapply a waterproof finish.
  • Replace swollen, warped, or rotted cabinet wood panels and structural boards. Match existing cabinet finish.
  • If the cabinet floor/base is damaged, it will likely need replacing. Cut out damaged sink base and install new matching cabinet piece after leak repairs are complete.
  • Use water damage resistant materials like marine plywood for any replacements.
  • If subfloor or drywall is affected, cut out up to 12 inches above the waterline and replace with new, mold-resistant materials.

Preventing Future Water Damage

While repairing existing water damage under the kitchen sink, it’s wise to take preventative steps as well:

  • Have any leaky pipes or joints repaired by a professional plumber.
  • Install leak detection devices that sound an alarm when water is detected.
  • Improve ventilation under the sink with ventilation grids or fans to discourage condensation.
  • Seal any cracks and openings with caulk to prevent moisture intruding under the sink.
  • Consider waterproof sink base materials like silicone or linoleum rather than particle board.

Take prompt action at the first sign of water under the kitchen sink to prevent extensive damage. Regularly check under the sink for potential leaks or moisture to stop water damage before it starts. Invest time and money upfront to waterproof the area, and it will save on major repairs down the road.

Signs It’s Time to Call Water Damage Restoration Experts

While some instances of water damage under a kitchen sink can become DIY projects, it’s smart to call in a professional water damage restoration company when you notice:

  • Standing water remains under cabinet 24 hours after extracting the initial leak, flood or overflow. Slow drying promotes mold growth quickly.
  • Soft, swollen spots in walls or floors surrounding the kitchen sink from excessive moisture penetration. This indicates greater structural damage.
  • Visible mold growth on walls or cabinets under the sink, especially if occurring within 48 hours of initial water damage. Mold spreads rapidly.
  • A persistent musty, damp odor under the sink even after thorough drying attempts. Lingering smells mean excess moisture remains.
  • Warped or detached lower kitchen cabinets from chronic moisture exposure under the sink. Excessive swelling, bubbling or stripping of cabinet veneers demonstrates major water damage.
  • Evidence the leak originated inside a wall or from a source other than directly under the kitchen sink itself. This complicates locating, accessing and repairing the originating leak.

Water damage restoration companies have commercial grade:

  • Water extraction equipment to rapidly remove standing water out of walls, floors and tight spaces.
  • Truck-mounted drying systems that force warm, dry air through flooded areas to fully dry in hours instead of days.
  • Advanced disinfectants that completely kill dangerous mold hiding in saturated drywall or crawlspaces.
  • Moisture detectors that pinpoint any remaining dampness for directed drying efforts.
  • Licensed contractors to repair damaged walls, flooring, and cabinets to proper codes.

Don’t take chances with major water damage under your kitchen sink turning into an even costlier restoration project by delaying too long. Call water damage restoration experts at the first signs of substantial impact beyond the sink itself. They have the tools and knowledge to dry, disinfect, repair, rebuild and restore your kitchen properly.

How Much Does it Cost to Repair Water Damage Under a Kitchen Sink?

Minor water damage confined only to the interior of the kitchen sink cabinet can often be repaired for less than $200 in supplies when done as a DIY project. Replacing just a damaged sink base cabinet floor panel typically costs $50-100.

However, if adjoining walls, floors or structural framing is affected, repair costs rise exponentially, with professional restoration easily costing thousands. Factors impacting water damage repair costs under a kitchen sink include:

  • Size of the affected area – Is damage contained to just the sink cabinet interior or has moisture spread to walls and subfloor? A few replaced customizable cabinet wood panels is cheapest while an entire custom built cabinet, flooring and wall reconstruction is most expensive.
  • Extent of demolition/rebuilding needed – The greater the tearing out and replacement of walls, floors, tiles, and cabinets, the higher the water damage repair bill. Basic cleaning, sealing and painting intact structures is quickest and cheapest.
  • Drying method necessary – Simply air drying a sink cabinet may suffice in small spaces while larger flooded areas need equipment like dehumidifiers ($40-200 daily rental), air movers, and truck-mounted drying systems costing thousands for extensive projects.
  • Mold remediation – Detecting and eliminating mold from wet walls, wood and other porous surfaces ups costs especially if certified professionals are required for safe removal and disposal regulations. Bleach solutions work for DIY minor mold cleanup.
  • Plumbing repairs – Simple P-trap or slip joint replacements under a sink may cost $30-60 in parts while re-piping an entire home’s water supply and waste lines can run thousands to tens of thousands. Unexpected leaks often require drywall and floor access demolition too.

On average, minor DIY sink cabinet repairs run $100-500 using moisture meters, sealants and replacement cabinetry panels. For professional sink cabinet water damage drying, cleaning, repairs and mold remediation, costs often reach $2,000 to $5,000+. Major repairs affecting multiple rooms or structural rebuilding can cost over $10,000.


Dealing with water damage under a kitchen sink as soon as it’s noticed is crucial to prevent structural deterioration, mold growth, foul odors and much costlier repairs later. While some instances of minor sink cabinet flooding can become DIY weekend projects to address, larger affected areas or already visible mold requires calling professional water damage restoration contractors. Their commercial grade drying equipment, disinfectants and expertise repairing flood damage properly to prevent future issues is invaluable compared to replacing entire walls or floors later which can cost many thousands. Be proactive, not reactive, to best protect your home from water damage threats like leaky sink plumbing.


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