If you notice water seeping from under your car door, there are a few things you can do to seal the leak. The first step is to determine where the leak is coming from. Look for signs of water damage, such as wet carpeting or a puddle on the floor. Once you know where the leak is, use a plunger to suction onto the area and push and pull until the water comes out. If you don’t have a plunger, try using a bucket or another container with a tight-fitting lid. ..