Reverse Osmosis (RO) filters are highly capable water treatment systems. With technology originally developed to desalinate seawater, RO home systems pack a serious punch, filtering your mains supply down to the size of individual molecules and ions. This makes reverse osmosis a common choice for those looking to ensure water safety—either from potential viruses and bacteria in private well systems, or the heavy metals that can remain in old pipes and plumbing.
Whatever your need for advanced home-filtering, we’ve put together a list of the best reverse osmosis systems you can buy today. Scroll down for the details.
Osmosis is the natural migration of water across any semi-permeable membrane. Left to its own devices, water will always move across a membrane in the direction of the space with the most dissolved solutes, seeking out the highest concentrations of particulates or contaminants in order to create an equal distribution across the whole body of liquid.
Reverse osmosis takes this water flow gradient and reverses it, applying an external force to make water travel across a series of semi-permeable membranes from a more concentrated to less concentrated solution.
These membranes are so fine that they can effectively remove contaminants almost down to the size of water molecules themselves (0.0005 microns in some systems!) Usually, an RO filter will employ three to five membranes, descending in filtering size, with the first designed to take out large particles of sediment, while the final membrane targets viruses and bacteria.
All of this gives RO filters the power to remove common waterborne and disease-causing protozoa, such as cryptosporidium and giardia. They’ll also easily rid your H2O of bacteria like E. coli, and take care of viruses such as the norovirus. As confirmed by the CDC, an NSF-certified RO filter will also deal with harmful metals like chromium and lead, which can leak into your water supply from old pipes and degrading fittings.
For those who need to go deeper into the how’s and why’s of reverse osmosis, here’s our extended look at Everything you need to know about reverse osmosis filters.