FAQ

Considered to be one of the most all-around effective ways to remove harmful contaminants. Removes up to 99% of impurities including lead, asbestos, PFAS among others.

Reverse osmosis (RO) is a separation process that uses pressure to force a solution through a membrane that retains the solute on one side and allows the pure solvent to pass to the other side. More formally, it is the process of forcing a solvent from a region of high solute concentration through a membrane to a region of low solute concentration by applying a pressure in excess of the osmotic pressure. This is the reverse of the normal osmosis process, which is the natural movement of solvent from an area of low solute concentration, through a membrane, to an area of high solute concentration when no external pressure is applied. The membrane here is semipermeable, meaning it allows the passage of solvent but not of solute.

In modern home units water, driven by normal city water pressure, flows first through a sediment pre-filter which removes any dirt and small particles that are in the water, next a carbon pre-filter, which removes organic contaminants including chlorine and its by-products. Then, it enters the reverse osmosis membrane, a very tight, sheet-like filter, which allows water to pass but rejects dissolved solids like sodium and impurities like lead and arsenic. Some of the water entering the unit is used to cleanse the membrane surface and flows to the kitchen drainpipes. The purified water is stored in a small storage tank until it is needed. When the faucet mounted on the sink is opened, the purified water is forced by air pressure through another carbon filter, which gives it a final polish and from there to the faucet. (This is a simplified description of a four-stage RO unit. The simplified description omits a few very essential parts like flow control devices, check valves, and an automatic shutoff device that stops the inflow of water when the storage tank is full.

It depends on what you mean by waste. A home RO unit uses water to clean itself and wash away impurities. It’s like a lot of other water-using appliances. We use water to wash clothes, to wash dishes, to wash cars, to flush toilets. A reverse osmosis unit uses more water in its operation than you actually consume, but it doesn’t use enough that you’ll notice it on your water bill. It uses water only while it’s filling its storage tank. When the tank is full, the whole unit shuts down and no water runs to drain. It is typically like two or three extra toilet flushes a day.

Yes, if you can reach it with a 1/4″ tube from the under sink RO unit. Pressure is a consideration with some refrigerators, so it’s a good idea to check with the manufacturer. The pressure you’ll get from the RO unit is about 2/3 of the incoming line pressure.

Virtually forever if you service it regularly and replace parts that wear out, like the storage tank and the faucet. Typical membrane life is about 2 to 5 years, depending on the nature of the water that it’s processing.

No, they run on water pressure. You need electricity only if you add an electric pressure-boost pump or an ultraviolet lamp. Standard units have neither and normally don’t need them.