If you are looking for a water filter, there are many options on the market and several types, each with pros and cons. The most basic is a water pitcher with a carbon filter, which is quite efficient. You can also get a filter that fits on a faucet or water supply.
If you want your water to be as clean as possible, a reverse osmosis (RO) system is the filter to choose. It pushes water through a very fine membrane that removes the great majority of dissolved contaminants. Below we compare six RO systems, from budget under-sink models to a tankless and a premium remineralizing system, followed by a short buying guide. If you are also thinking about the water in your shower, see our shower filter buying guide.
| Product | Our Rating | ||
|---|---|---|---|
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Best overall
iSpring RCC7-BN 5-Stage Under Sink Reverse Osmosis Water Filter, 75 GPD, NSF Certified |
VIEW ON AMAZON | |
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Best value brand
APEC Water ROES-50 5-Stage Under Sink Reverse Osmosis System, 50 GPD |
VIEW ON AMAZON | |
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Best budget
Geekpure 5-Stage Reverse Osmosis RO Drinking Water Filter System, 75 GPD |
VIEW ON AMAZON | |
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Best high output
Hydro-Logic 31040 Stealth-RO300 Reverse Osmosis Filter, 300 GPD |
VIEW ON AMAZON | |
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Best tasting water
Home Master TMAFC Artesian Full Contact RO System, 7-Stage with 2-Pass Remineralization |
VIEW ON AMAZON | |
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Best tankless
Waterdrop G2 Tankless Reverse Osmosis System, 400 GPD, NSF/ANSI 372 Certified |
VIEW ON AMAZON |
Best Reverse Osmosis System Reviews in 2026
Best Traditional Under-Sink Reverse Osmosis Systems
1. iSpring RCC7-BN 5-Stage Under Sink Reverse Osmosis Water Filter, 75 GPD, NSF Certified
The iSpring RCC7 is one of the best-known under-sink RO systems. It is certified to NSF/ANSI 58 and removes up to 99 percent of more than 1,000 contaminants, including PFAS, chlorine, fluoride, lead (up to 98 percent), arsenic and asbestos, and it reduces total dissolved solids by 80 to 90 percent. A brushed nickel faucet is included.
- 5-stage under-sink RO system, 75 GPD
- NSF/ANSI 58 certified
- Reduces PFAS, chlorine, fluoride, lead, arsenic and more
- Brushed nickel faucet included
- Certified performance from a very well-known brand
- Excellent owner ratings from a very large number of buyers
- Reduces TDS and the minerals that cause scale
- Easy to find replacement filters
- Sensible price for a complete 5-stage system
- Needs space under the sink for the tank and filters
- Wastes some water while making purified water
Our Verdict: Our top pick: a certified, proven and well-supported RO system with excellent owner feedback.
2. APEC Water ROES-50 5-Stage Under Sink Reverse Osmosis System, 50 GPD
The APEC ROES-50 is a reliable 5-stage RO system that makes up to 50 gallons a day. It removes arsenic, chlorine, lead, fluoride, heavy metals and more than 1,000 impurities from tap water and helps protect against PFAS, and it uses large, long-lasting filters.
- 5-stage filtration, 50 gallons per day
- Removes up to 99.99 percent of impurities
- Targets arsenic, chlorine, lead, fluoride and PFAS
- Large, long-lasting filters
- The lowest price among the brand-name systems here
- Large filters that last
- A trusted, long-established water-filter brand
- Highly rated by owners
- 50 GPD is on the low side for a large family
- Needs space under the sink for the tank and filters
Our Verdict: A solid, affordable system from a trusted brand, perfect for most small families.
3. Geekpure 5-Stage Reverse Osmosis RO Drinking Water Filter System, 75 GPD
Geekpure’s budget 5-stage system produces 75 gallons per day with a 2.8-gallon storage tank and filters down to 0.0001 micron. It reduces arsenic, lead, fluoride, cadmium and heavy metals, and it has NSF-certified tubing, a tank and membrane, and it fits most under-sink cabinets.
- 5-stage RO, 75 GPD at 60 psi
- 2.8-gallon storage tank
- NSF-certified tubing, tank and membrane
- Fits most under-sink cabinets
- Low price for a complete 75 GPD system
- Compact tank fits many cabinets
- Solid owner reviews
- Reduces arsenic, lead and heavy metals
- Brand is less well known than iSpring and APEC
- Smaller range of replacement filter sources
Our Verdict: A budget-friendly choice that still includes a complete 5-stage system.
4. Hydro-Logic 31040 Stealth-RO300 Reverse Osmosis Filter, 300 GPD
The Stealth-RO300 is a high-output RO system rated for up to 300 gallons per day. It wastes about 25 percent less water than other RO systems, has an automatic shut-off cartridge and comes with a wall-mountable metal bracket, which makes it popular for tanks and garden use as well as home drinking water.
- Up to 300 gallons per day
- Wastes about 25 percent less water than comparable systems
- Automatic shut-off cartridge
- Wall-mountable metal bracket
- High output for large households or heavy use
- Lower water waste than conventional units
- Metal wall bracket for flexible installation
- Compact design
- Owner feedback is not as strong as for iSpring or APEC
- More output than most households actually need
Our Verdict: A high-capacity option when you need a lot of water per day.
Best Premium and Tankless Reverse Osmosis Systems
5. Home Master TMAFC Artesian Full Contact RO System, 7-Stage with 2-Pass Remineralization
The Home Master Artesian Full Contact is a higher-end RO system that addresses the flat taste of ordinary RO water. A patented two-pass alkaline remineralization stage adds calcium and magnesium twice during the purification process, and a fast 4.5-second fill rate gives you water quickly.
- 7-stage filtration with patented 2-pass remineralization
- Fast fill rate
- Full-contact design that avoids common canister-RO issues
- Adds calcium and magnesium to the water
- Water tastes better, thanks to the added minerals
- Top owner rating in the group
- Robust design built for long life
- Fast fill rate means less waiting
- The most expensive brand-name system
- Large installation footprint under the sink
Our Verdict: The best choice for taste: mineral-enriched water and the highest owner rating, if you accept the higher price.
6. Waterdrop G2 Tankless Reverse Osmosis System, 400 GPD, NSF/ANSI 372 Certified
The Waterdrop G2 is a compact tankless RO system with a 400 gallons-per-day output and a 1:1 pure-to-drain ratio, which wastes far less water than traditional tank systems. It fills a cup in about 12 seconds, uses a composite filter and is certified to NSF/ANSI 372 for lead-free materials.
- Tankless design, 400 GPD
- 1:1 pure-to-drain ratio
- NSF/ANSI 372 certified, composite filter
- A cup of water in about 12 seconds
- Tankless design frees up lots of space under the sink
- Wastes much less water than tank systems
- Fast, steady flow
- Easy installation and replacement filters
- Needs an electrical outlet under the sink for the pump
- Costs more than the basic tank systems
Our Verdict: Perfect for small cabinets and for people who dislike wasting water.
Pros and Cons of Reverse Osmosis Systems
Pros: your water is clean and free from many impurities, odors and tastes are removed, maintenance is minimal, the systems are easy to use and the water is healthier for baby formula, tea and coffee.
Cons: not every RO system blocks chlorine, pesticides and herbicides on its own, so you often need carbon filters as well. Traditional systems waste about 2 to 3 gallons for every gallon of purified water, the unit and replacement filters cost money, and RO can remove beneficial minerals unless the system remineralizes the water.
How to Choose the Best Reverse Osmosis System
- Size and capacity. For drinking water, a smaller under-sink system is usually enough. If you want filtered water for bathing and cleaning too, consider a whole-house system instead.
- Contaminants. Find out what is in your local water and choose a system certified for it. More stages usually means cleaner water. Look for NSF/ANSI 58 or 372 certification.
- Tank or tankless. Tank systems fill slowly into a storage tank. Tankless systems produce water on demand, take less space and waste less water, but they need electricity.
- Water waste. Check the pure-to-drain ratio, because efficient systems waste much less water.
- Filters and maintenance. Factor in the cost and availability of replacement filters.
- Taste. Some systems add minerals back, which makes the water taste better.
How Much Does a Reverse Osmosis System Cost?
A good RO system starts at around $150 to $200. The more features it has, such as extra stages, remineralization, tankless design or alkaline filtering, the more it costs, but a basic 5-stage system is enough for many homes.
Related guides
For other ways to improve the water in your home, see our electric tankless water heater reviews.
