There are basically 3 reasons to get a pool cover, all of which are completely necessary if you are going to take on the responsibility of owning a swimming pool: 1) you need to protect your swimming pool water from dirt and particles that can clog your drain, 2) chemicals can evaporate if your pool is not properly covered, and 3) covers serve as a protection devise so that children and pets do not fall in. With that in mind, you now need to figure out which type of pool cover you need.