How Does Reverse Osmosis Work?

Whether you’ve got hard water or simply strange-tasting water from the taps in your home, it’s not usually the best to drink. Fortunately, water purification systems give you the ability to create clean drinking water right in your own home so you don’t have to keep buying bottles or lugging heavy flats home from the grocery store.

One of the most popular water filtration systems is a reverse osmosis system. Reverse osmosis is a unique method of filtration that has a number of advantages. For starters, a reverse osmosis system is low-cost with a brand new unit running about a few hundred dollars or so (which pales in comparison to the price of buying bottled water for a year). Second, they’re extremely simple to install, requiring nothing more than a small addition to your main water line and drain line, plus a little bit of space under the sink. Finally, they require little to no maintenance whatsoever, and can provide you with a supply of clean water for years before needing replacement. They also use no energy, which means you won’t have to worry about yet another drain on your already rising electric bill.

Here’s how the process works.

Intake

The process starts by your system pulling in a steady stream of water from your home’s water supply. Usually this link is connected to the main water line that feeds your kitchen sink. From there, your household water pressure actually pushes the water against a series of thin, semi-permeable membranes. The holes in this membrane are so small that they only allow water molecules to get through, all while removing everything from lead to pesticides to nitrates and sulfates from the water.

Cleansing

The first membrane is known as the “pre-filter” which removes sediment and carbon-based inclusion from the water. This is arguably the most important filter for your system as it’s designed to remove the largest and most damaging inclusions in your water ahead of time and protect the thin, delicate reverse osmosis membranes that remove other contaminants that can be even more harmful. This step may also remove chlorine as well, which can be hazardous to reverse osmosis membranes. The sand and sediment that’s removed in this step is flushed away.

The water then proceeds through the heart of your reverse osmosis system: a reverse osmosis membrane. This thin membrane removes everything from ugly colors and smells to unhealthy chemical contaminants from your water, leaving you with clean drinking water to enjoy.

Depending on your system, at this point your water may or may not go through one final filtering process: a carbon “post filter” which is sort of a “polish” for your drinking water. This removes any remaining odors or funny tastes from your water. At this point, the contaminated waste water is flushed away down the drain and the water that’s left is sent to a reverse osmosis storage tank.

Accessing Your Water

The storage tank in an average reverse osmosis system is anywhere from two to four gallons in size. Generally, the larger your household, the larger the system you’ll want. The water is stored inside a bladder in the tank which keeps it under a moderate pressure and allows it to feed through the water line out to the faucet where it is distributed into your waiting cup or bottle. Reverse osmosis systems use their own faucet which is typically installed on your kitchen sink next to your regular faucet.