If you’re keen to purify your tap water, reverse osmosis is one of the most effective solutions. RO filters can remove up to 99.99% total dissolved solids in drinking water sources, eliminating chemicals like chlorine, heavy metals like lead, microbiological contaminants like bacteria, and even difficult-to-remove impurities like fluoride.
Reverse osmosis is so popular today that there are endless choices on the market. Trying to decide on a single RO system can feel quite overwhelming, especially if you’re not entirely sure what you’re looking for.
This guide will discuss how to choose the right RO system, and the factors to consider when deciding on the best filter for your needs.
Understand Your Water Source & Contaminants Present
First, you need to know exactly what you’re dealing with in your drinking water source. Getting your water tested by a private laboratory will help you to determine which contaminants pose the biggest problems in your water, and which you want to remove.
Reverse osmosis filters can remove almost every existing drinking water impurity, but knowing what contaminants your water contains is still helpful when you check a system’s contaminant removal capabilities when deciding on a purchase.
Know Your Water Pressure
Water pressure is another important factor when purchasing a reverse osmosis filter. Most RO systems require a water pressure of at least 60 PSI to operate. The reason for this is that a reverse osmosis filter needs enough pressure to force water through the semipermeable membrane.
If your water pressure is lower than 60 PSI, you may benefit from buying a booster pump, which will increase your flow of water before it reaches the RO filter.
Figure Out Your Daily Requirement of Purified Water
How much purified water will you need per day? If you just want purified drinking water (which is the most popular option), it should be easier to find a system that meets your requirements. There are larger-capacity whole-home RO filters, but these are less common than point-of-use systems.
Tank size is something to look at if you have particularly high water filtration demands. You need to make sure you buy a system with a tank that is large enough to provide you with all the filtered water you need when you turn on the tap. Of course, you could choose a tankless system that produces RO water on demand if you think you might use big batches of water at once.
Select the Type of System
There are several types of reverse osmosis system to choose from, including countertop, under-sink, with or without tank, and whole house reverse osmosis filters.
Countertop RO filters are standalone filters that need to be plugged into electricity to operate. You add water to the filter tank, and the system filters it in a single batch.
Under-sink RO filters are hooked up to the cold water line under your kitchen sink and filter water before it leaves the faucet.
Whole-house RO filters are installed at your home’s point of entry and provide purified water to your whole home, including your showers, appliances and sinks.
Tank-based RO filters store water in a tank, so that when you turn on your faucet, you’ll get access to already-filtered water.
Tankless RO filters have no tank, and produce filtered water on demand.
Consider System Efficiency
RO systems can vary widely when it comes to efficiency.
A traditional reverse osmosis filter has a 4:1 wastewater to pure water ratio.
You can now purchase more modern systems that only waste 1 or 2 gallons of water for every 1 gallon produced - and the most modern, efficient systems that only waste half a gallon.
If you want to keep water waste to a minimum, it’s worth paying extra for a system offering a more efficient performance.
Research Filter Longevity
The average RO filter lifespan is 6-12 months for the pre-filter, 12 months for the carbon filter, and 2 years for the reverse osmosis membrane.
It's worth looking into filter lifespan before you buy an RO system, so you’re aware of (and happy with) your maintenance commitments in advance.
Think About Remineralization Needs
Reverse osmosis filters everything out of your water - including healthy minerals like calcium and magnesium. If you want to add these minerals back into your water, you can do so, either by using mineral drops or with a remineralization filter.
Some RO filters come with included or optional remineralization filters, and are a good option to consider if you’d rather drink purified, mineral-rich water.
Consider Space Available for Installation
Finally, look at where you plan to install your reverse osmosis system, and how much available space you have. There are many space-saving RO designs on the market today, including tankless systems, and these may be a better choice if you don’t have much countertop or under-sink space available.
It’s worth measuring the planned installation location and making sure there’s enough room for maintenance before buying a system.