Floods, hurricanes, even leaking pipes, drains and tubs can cause brown, black or yellow water stains on your walls and ceilings. The first step to removing them is fixing the cause of the leak to ensure it doesn't come back. Then you can go ahead and remove the stain by cleaning the area, lightening the colour and painting over the stain, if necessary. Purchase stain-killing primer at a hardware or home improvement store.
Remove furniture from the room and spread plastic dust sheets on the floor below the stained ceiling and wall.
Put on gloves and goggles to protect yourself from the harsh chemicals. Goggles are especially important because you will be applying solution to the ceiling where it could drip back in your face.
Mix a solution of 1 part bleach and 1 part water.
Dip a sponge into the solution and rub it over the watermarks. This will remove any mould or mildew growth and lighten the stain.
Mist the area with clear water from a spray bottle to remove as much of the bleach-based cleaner as possible.
Dry the area completely with cloths and let it air dry before painting it.
Brush stain-killing primer onto the stained area of the ceiling and walls. Use a mildew- or mould-fighting primer if you are working in an area of your home that has experienced mould problems.
Let the primer dry completely.
Apply one or two coats of ceiling and wall paint to match the rest of the room.
Let the area dry completely before removing the dust sheets and putting the furniture back in place.
Never attempt to remove water stains before you've fixed the leak, as the leak will likely return and bring the stain back with it.
Always work in a well-ventilated area when working with bleach.