What to Do About Water Leakage in Your Wall

wall water leak

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Having an unidentified leak is nerve-wracking. There is no way to know the extent of the issue or damage being done until you find and repair the source. If you suspect there is a leak inside of a wall, don't panic—you may be able to address it without major maintenance or shelling out for a repair.

Identify The Leak

Water leaks are often because of pinholes in your plumbing system or small failures in caulking or other exterior materials. Water takes the easiest path down to the ground, so it will often travel along the framing in the walls. If you are not sure, use a moisture meter to find out if the moisture levels in your home are within normal parameters and an infrared camera to look for leaks behind walls and ceilings.

Signs You May Have a Leak

  • Wet or discolored drywall
  • Water-stained trim
  • Damp masonry
  • Musty smells
  • Mold or mildew
  • Puddles on the floor near walls or drips from the ceiling

Potential Sources

Once you confirmed you do in fact have a leak, you'll need to identify the source. Where you see the water or moisture may not be right where the leak is, so this can take some sleuthing.

Interior Plumbing

To determine if the leak is coming from defective plumbing, turn off all faucets and appliances that use water in your home, and write down the number on the water meter. Wait at least three hours, and check the water meter again. If the amount of water used increases, that's a good sign the leak is coming from indoor plumbing. This method is less effective in homes where toilets constantly run or faucets that drip, and your water meter will indicate a slight increase from the original number you wrote down.

Exterior Above Grade Issues

If indoor plumbing isn't the issue, move your inspection outside. Check for clogged gutters, downspouts, and compromised caulking, and inspect the flashing on exterior penetrations such as vents, chimneys, windows, and doors.

Exterior Below Grade Issues

If your leak is coming through at the lower level, you may have exterior below-grade issues. Common causes of this type of leak are broken sprinkler pipes, improper drainage from downspouts, or french drains or grading that slopes toward the house.

Repair The Leak

If your detective work has paid off, you now know where the leak is coming from. It's time to get to the repairs.

Interior Plumbing

If you found your water leak inside the wall, then you have more than a simple plumbing repair on your hands and it may be time to call in the pros. They would cut the wall open, determine the exact location of the leak, and replace the damaged sections. Then patch the wall, sand, prime and paint. If you have plaster or the leak is behind tile or brick, a professional contractor is your best bet.

Exterior Above Grade Leaks

Clogged Gutters and Downspouts: Gutters and downspouts should be cleaned and free from debris one or two times a year. Do regular inspections, even if you have gutter guards in place to make sure the water is flowing freely through the system and being diverted away from the house.

Caulking: Start with scraping out the old caulking. Make sure you have the correct type, for exterior projects, this is usually a butyl-rubber caulk. Cut the tube open, load up the caulk gun and apply at a 45-degree angle in a slow, consistent motion.

Flashing: Flashing refers to a metal barrier installed where the roof meets any vertical wall, such as chimneys, skylights or roof vents. There are three main types: base flashing, step flashing, and counter flashing. A chimney uses all three types to prevent water from coming in through your roof.


Repairing a leak of this kind is something most homeowners can do, but if the project involves extreme heights or a steeply pitched roof, you should call in a pro.

Exterior Below Grade Leaks

These are often the toughest to diagnose and repair.

Sprinkler System: Replacing a section of pipe in your sprinkler system will solve this issue. Plumbing novices should call a sprinkler company to handle the repair. Otherwise, the simplest method is to use compression couplings.

Downspouts: When coming through the downspout, water should be directed away from the house and foundation. Adjust the downspouts as necessary, or purchase extenders to get the water flowing to the right area.

Grading: Grading should always slope away from the house. Fixing the grading isn't as simple as piling up dirt near the foundation of the house, though. You need six to eight inches of clearance between your siding and the foundation of your home to prevent structural damage. Grading properly can require permits, and can often tear up your whole lawn. This is a project best tackled by a professional landscaper.

Basement Waterproofing: Your lower level walls may be in need of a full waterproofing system. On some homes, driveways, decks, patios or neighbor's homes prevent the waterproofing from being installed on one or more exterior walls. In these cases, the system can be moved inside by trenching out the floor, installing floor drains and a sump pump system to divert the water after it has come in.


Homes require timely maintenance to prevent leaks in the future. This has the added benefit of helping you spot potential issues before they occur. Make sure you:

  • Clean gutters and downspouts
  • Inspect exterior caulking and replace when necessary
  • Blow out your sprinkler system once per year (before winter in colder areas)
  • Test your sump pump
  • Replace any missing roof shingles

In addition to regular maintenance, you can:

  • Use pex piping where possible
  • Add a battery backup to your sump pump
  • Pay attention to the drainage patterns around the house
  • Insulate pipes on exterior walls in climates where they might freeze
  • Keep your water pressure between 40-60 PSI