Finding the Leak
There are a few ways to find the source of the roof leak. If you can go into your attic when it's raining, look to see where the water is originating. Make a mark next to this spot. After the rain stops, you will come back and insert a nail, ice pick or wire hanger to identify the leaking spot.
If you want to look while it's not raining, it's best to have some help. Go inside the attic while another person uses a hose on the roof. You should then be able to see where water is coming inside the roof. You may also see some sunlight which would indicate a hole. Use a long nail, wire hanger or ice pick to stick up through the roof where the hole is. Make sure your friend sees the marker - this will save a lot of time searching once you're on the roof.
Fixing the Leak
Once you have found the leak it's time to get on the roof. If the nail is raised, tap it back down. Spread Tripolymer Sealant over the nail and the hole you created while marking the spot. You can spread the sealant with a paint stick or some other disposable stick. The sealant is runny and will fill in any holes. It is also clear, so it worksto repair holes on any roof without being noticeable.
Wait a few days and test the spot in your roof with water to make sure that the leak is indeed fixed. This is a permanent fix. There shouldn't be a need to call a roofer if you get the hole filled with the sealant.
Always be careful when climbing on a roof. If you can't safely get to your roof or don't have the proper equipment to get there, it's best to call a roofer. Sometimes it's better to call a professional and spend a little extra money than to risk life and limb.