Collection: Reverse Osmosis Systems

Reverse Osmosis Filtration Systems

A reverse osmosis system pushes household water against a semipermeable membrane under pressure. Ordinary osmosis moves water toward the side with more dissolved material; pressure reverses that direction, so water passes through the membrane and dissolved solids stay behind and go to the drain. What comes out the other side is water with most of that dissolved load removed.

Most residential systems put the membrane in the middle of a sequence. A sediment cartridge comes first to keep grit off the membrane, a carbon stage follows to take out chlorine that would damage it, and a post filter polishes the water on the way to the faucet. Systems with additional stages carry the process further, and some add a remineralization stage to put minerals back after the membrane.

Standard systems store treated water in a pressurized tank under the sink so a glass can be filled quickly. Tankless systems produce water on demand with a booster pump, which frees up cabinet space and removes the stored tank from the equation. Models from manufacturers such as GE, Whirlpool, and Omni cover both formats.

System capacity is rated in gallons per day, and that number is the first thing to match to a household. A home that draws water for drinking, cooking, coffee, and an ice maker needs more daily output than a single person filling a pitcher. Available space under the sink and the number of stages a household wants both narrow the field from there.

Every stage in an RO system is consumable. Sediment and carbon cartridges are usually changed once or twice a year, and the membrane itself lasts longer, though incoming water quality and use both move those intervals, so check the manual for the system in question. A subscribe and save plan keeps the right cartridges arriving on schedule, which is what keeps an RO system producing the water it was sized for.