What to do about water stains?

You are installing a new light in your living room and suddenly notice there is a water stain on the ceiling!  Oh no!  Fortunately, this does not automatically mean that there is an issue going on, but you will want to investigate it.  Water stains on a ceiling can be caused by many things such as a leaky roof, or if you have a two-story or higher house, could be from a leaky bathroom or radiator (in certain parts of the country).  

It also could be from a one-time event.  Let’s take a look at what to do if you have a water stain on the ceiling.  Including, why this is important, identifying the cause, and how to fix it.  

Why This is Important

Not only are water stains a cosmetic issue, but they can also indicate that there is a leak in the home that needs to be fixed.  Sometimes, this may be the first indicator of a bigger problem brewing or may have been a one time leaky issue.  It is important to investigate to make sure it is under control before you possibly have thousands of dollars in repairs. 

Identify the Cause of the Water Stain on the Ceiling and Where to Start


It is important to identify the cause of the water stain on the ceiling first so you can fix it.  Start first with the roof to see if there are leaky shingles or missing shingles, missing flashing, or weakened seals around roof vents. You may need to get on top of the roof to look or call a professional to check for you. It is possible that water is coming into the home from the roof.  So you will want to have the professional take a look to see if this is the issue.  

Also, look in the attic to see if there is a pool of water and that will also help you to know if there is water leaking into the home. 

Radiator or air handler on 2nd floor

Radiator or Air Handler on 2nd floor

In colder parts of the country, there may be a radiator on the second floor.  Radiators are used to keep rooms warm in the cold months and do wear out or need replacing. Does the radiator have a pool of water underneath it or any dripping?  If yes, this could be the problem and causing the water stain on the ceiling.  Check the model of the radiator and see if it is something you can do yourself or call a professional to check the body, pipe, and the valve for leaks. 

The same is true for those who have an air handler on the second floor. Did your AC stop working? Or do you see water leaking?  The drip pan (if you have one) on an HVAC unit collects the water and it can become clogged and back up. The float switch (again, if you have one) will activate as soon as the water reaches a certain level and shut down the HVAC unit, thus not allowing the water to continue to flow. Make sure the HVAC doesn’t become clogged and checking this monthly is a good idea.

Upstairs Bathroom Can Cause a Water Stain on the Ceiling

Bathrooms are often the culprit as caulking wears out after about 10 years and needs replacing.  Is the home older than 10 years?  This may be the issue.  While checking the caulking in the bathroom around the sinks, toilets, and shower/bath, also check for black mold in the shower.  Might as well rule everything out while you are looking for the source. 

Other areas to look at are toilets clogging and overflowing.  Do you see water near the toilet on the floor?  This could be the seal is broken on the toilet and it needs replacing.  Also, adding caulk to the toilet to connect it to the floor is a good idea.  If the toilet is continuously running, you can shut off the water and do the water meter test. 

Write down the number on the water meter and then turn off the water for three hours. When you turn it back on, check the number on the water meter.  If it has increased, then you have a leak in the indoor plumbing. 

Taking care of these areas is essential as sewer gases can also be escaping.  Sometimes these issues will soak the ceiling below and clog in sinks and drains in the shower can also cause flooding in a bathroom. 

Pipes in the Walls

Another area is the pipes in the walls.  These can often leak or break without us knowing.  If you found there is a leak with the water meter test above, call a professional to do an infrared thermography inspection. Once you find where the leak came from, fix it, and then cover up the stain with the process below. 

How to cover the water stain on the ceiling

How to Cover the Water Stain on the Ceiling

Unfortunately, there are not too many ways to clean a water stain on the ceiling without using chemicals like bleach. 

1. Put a Drop Cloth on the Floor

  • With goggles on and gloves, put a drop cloth on the floor.  Then, take 3 glasses of warm water and one cup of bleach and mix it together.  Set up a ladder and climb up to the stain.  Use a sponge that is soaked in the concoction to rub it on the water stain to get it to come off.  Take a spray bottle of plain water and spray the stain to get the bleach mixture off.  This is important because you want to be able to prime it and paint it.  Take a dry towel and rub the stain to help it dry faster. 
  • Next, put painters tape around the ceiling if the spot is near the walls. 

2. Apply an Oil Based, Stain Blocking Primer

  • Apply an oil based, stain blocking primer that is mold resistant that matches the ceiling.  It is important to put the primer on first so the paint doesn’t soak into the ceiling.  If you have a flat ceiling, you can use a paint roller with an extension to apply it.  Once the primer has dried, apply the paint.  If you have a textured ceiling, a spray on primer might work better. 

3. Choose a Latex or Alkyd Ceiling Paint

  • The latex ceiling paint is water-based and dries faster than the oil-based paints and also is thicker than wall paint. Make sure that the paint matches the ceiling color. Using a roller, paint it on over the primer and let it dry for up to four hours. Then, apply a second coat and let it dry.  The second coat should make the stain disappear. 

If you want to try removing the stain and not paint over it, here is an idea of how to do that:

When to Call a Professional for a Water Stain on the Ceiling

Call a professional if you find the source of the leak and can’t fix it or if you need help finding the leak. It is important that it is found and taken care of before you move on to priming or painting.  You want to stop the problem before there is a large expense to fix an issue you could have fixed early on. A professional can help you do that and help with any of the areas mentioned above.  Don’t be afraid to ask for help!


Stains on a ceiling are not only a cosmetic issue but also sometimes an indicator of bigger issues lurking on the second floor or roof or in the walls or bathroom. The good thing is a stain can be covered up on the ceiling with bleach, warm water, primer, and paint.

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