Which Is the Best Under Sink Water Filtration System for Me?

Two types of under sink water filtration systems are best at packing a heavy punch: three-stage reverse osmosis (RO) water filtration systems and two-stage products. Both are practical options to install under sinks in kitchens or bathrooms, and both are good for reducing contaminants to provide you with cleaner water.

Which of the two water filtration systems for use under a sink is best? Though they’re both effective tools in helping clean your water, each has its own unique advantages that could better suit your home. Knowing which is the right choice for you can go a long way in boosting the quality of your water supply for years to come.

Three-Stage RO vs. Two-Stage Water Filtration

What filtration system is most effective?

Reverse osmosis systems provide the most thorough filtration possible and are proven to be among the best water filtration systems installed under the sink. They boast a semipermeable membrane that separates contaminants—including chlorine, lead, sediment and microbial cysts—from your drinking water.

Like two-stage products, RO systems fit under the sink. However, they have a separate water storage tank that needs to be installed. If you live in a home with limited storage under your sink, it may be necessary to install the tank in another room, basement or garage, which may require some additional plumbing work. RO filtration systems require new pre- and post-filters once every six months (depending on your water quality) and their membranes can last two to three years.

Two-stage under sink models are also effective at reducing common contaminants—such as chlorine, lead and sediment—from your faucet’s water supply. Like RO systems, their filters need to be replaced every six months using the same twist-off, twist-on process. There is also no water storage tank to take up additional space.

Are under sink water filters worth it?

Installing a water filtration system under your sink isn’t just a convenience, it can also save you money. With regular access to great-tasting, cleaner water, you can ditch buying bottled water while reducing plastic waste. The water filtration systems themselves are also low maintenance, with filter replacement being a cinch.

When deciding what is the best home water filter system for under your sink, in the case of three-stage reverse osmosis versus two-stage filtration the final decision may come down to accessibility. RO systems, though a little more advanced in contaminant reduction, take up more space than their two-stage counterparts—space you may not have. Two-stage models still pack a punch and are good for reducing most contaminants, including chlorine and lead. You also won’t have to worry about additional plumbing when choosing a two-stage unit.

Know that whichever water filtration system you deem best for under your sink, your days of relying on bottled water for drinking are coming to an end.