A key point in the use of skylights is their tightness. That is, if a skylight starts leaking water, you have problems. Naturally, the best way to prevent this issue from occurring is to have purchased high quality skylight. Unfortunately many people believe that a skylight is just a skylight, and does not need to be of a high quality. This is most certainly not the case. Whilst the light provided by a skylight, as well as the air circulation it generates do not depend on the quality of the skylight, it is factors such as tightness and its capability of insulating in the winter months that change according to the quality. Therefore, the best way to prevent a leaking skylight is to buy a high quality one. If you have not done this, and are finding that your skylight is in fact leaking, there are several things that you can do to stop this. The easiest way to do this would of course be to simply call up a company that does it for you. They will fix the skylight, and charge you for it. Simple. If you are more of a DIY kind of person, you may prefer to fix the skylight yourself. This is best done using an insulation product in a can, where foam exits the can and solidifies on contact with the surface. This, I find, works very effectively, and stops any issues with leaking, although if the low quality of the skylight is at fault, the problem may reappear elsewhere. I hope that this helps you in combating any leakage that may occur in your skylights. If you are planning to purchase skylights, just remember, buy high quality.