Leak in the Ceiling Below a Bathroom

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Leaks in the ceiling below a bathroom usually mean your toilet, sink or bathtub are leaking. Water leaks from a plumbing fixture or pipes may go unnoticed for days or even weeks, until you notice a wet spot or water stain on the ceiling below. It takes a little detective work to find the source of the leak to repair it. Once you see that the water is coming through the ceiling, take immediate action before it causes any more damage to your house.


How to Find the Source of the Leak

Just because you find a leak in the ceiling below a bathroom doesn't mean you necessarily know exactly where it's coming from. Leaking water doesn't always fall straight down — instead, it can run along pipes, floor joists or other surfaces before falling onto the ceiling below. Even if the leak appears below the sink, it could actually be coming from the toilet or tub. If the leak is below a different room, it could be traveling from the upstairs bathroom.


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  1. Start by looking in the bathroom that you suspect the leak is coming from.
  2. Look at the fixtures in the bathroom and visually inspect them for leaks.
  3. If you can't find it after looking at the fixtures, cut a hole in the ceiling and look around with a flashlight to positively identify the origin of the leaking water.
  4. Use plumbing access doors such as the one found on the wall behind some shower or bathtub faucet to look inside the wall for the leak.


How to Identify and Repair Toilet Leaks

If your toilet is the origin of the leak, you may see water pooling around the toilet, or the floor around the toilet will feel almost spongy. If the leak seems to be coming from the toilet's tank, drop food coloring in the tank's water and wait to see where the colored water exits the tank. Tighten loose parts, or replace those that leak even after you have tightened them.


If the leak doesn't seem to be coming from the toilet tank, it may be resulting from a loose connection between the base of the toilet and the waste pipe in the floor. In that case, you must:

  1. Unseat the toilet.
  2. Scrape off the old wax ring.
  3. Inspect the floor flange for damage.
  4. You then need to replace the wax ring.
  5. Seat your toilets so they don't rock in any direction; otherwise, the toilet could leak again in the future.


How to Identify Bathroom Sink Leaks

You'll see water damage or pooling water in the cabinet below the sink if the sink's drain or pipes are the origin of the leak in the ceiling below a bathroom. Tightening the retaining nut on the drain body or the connections between the pipes will eliminate some leaks at the joints. If your pipes don't have plumber's tape on the threads, the pipes may leak even though the connections are tight. If you find it difficult to tell the origin of a leak, dry off the pipes and use a tissue to determine if water comes out of a specific location.


How to Identify Bathtub and Shower Leaks

If you suspect the shower or bathtub is the origin of the leak, use a bucket to determine if the water supply lines or drainpipes are the cause. By running the faucet but filling up a bucket instead of letting the water go down the drain, you will see if the leaking continues or stops. If the leaking continues, you know the water supply pipes are the cause.




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