The best water treatment plant manufacturesIf you want to compare drinking water systems, one of the first questions you'll ask is, "What does reverse osmosis do, as opposed to a filtration system?" That is what you will learn in this article. I think once you have some answers, you'll start asking, "Why would anyone choose a reverse osmosis drinking water system?" So, what is reverse osmosis? Reverse osmosis is a physical process that is the opposite of osmosis. Osmosis occurs naturally in plants, where two fluids of different salinity are separated by a semi-permeable membrane. Water in the less saline fluid will move through the membrane into the more saline fluid until the two have equal salinity. It turns out if the more saline fluid is under pressure and the other fluid isn't, water will move from the more saline fluid into the less saline fluid. So if you have seawater on one side of the membrane and fresh water on the other, and you apply pressure to the sea water, you'll get more fresh water. This is an extremely useful process, and is a preferred method for desalinization of seawater.