Having a leak in the roof of your car can cause damage when it rains will damage your upholstery as well as trickle water into electrical circuits, Fortunately, repairing roof damage is relatively easy and will save a lot of money in getting it repaired professionally --- especially if your car is out of warranty.
Inspect the roof of your car and to find the source of the leak. Ask a friend to stay inside the car while you spray water over the roof. Your friend should be able to identify where the water is coming in.
Check common problem areas, such as the seal around the windshield or sunroof. When you have found the leak, dry and clean the area with a rag.
Purchase a roof sealant from a hardware or auto store. Following the manufacturer's instructions, apply a small amount of sealant to the area and use a piece of cardboard to evenly cover the hole.
Use the garden hose to retest the roof for leaks.
You should get your car repaired professionally if it is under warranty.