Which reverse osmosis system is best?

Reverse osmosis is a process that removes impurities and contaminants from unfiltered tap water. Water from the municipal supply is forced through filters and membranes to remove dissolved solids. The system fits under your kitchen sink and delivers filtered water by way of a separate, dedicated faucet. 

Reverse osmosis systems are cost-effective, healthy and green solutions for people who want filtered water because it is purer and tastes better. If you are looking for a reverse osmosis system that is tops in performance, water quality and customer support, take a look at the Home Master TMHP HydroPerfection Reverse Osmosis Water Filter System.

What to know before you buy a reverse osmosis system

System size

Reverse osmosis systems have a tank, some simple plumbing, filters and a separate faucet. The filtration part fits under your kitchen sink, and that’s where the size of the unit you choose is essential. Look for reverse osmosis systems that fit easily underneath your sink while leaving you plenty of room for the other things you keep there.


For filters to work correctly, they need to be changed frequently. Different reverse osmosis systems use different numbers and types of filters. The difference in the cost of replacing them according to manufacturers’ recommendations will vary a great deal. 


These letters refer to the number of Gallons Per Day your reverse osmosis system will produce. As the number of GPD produced by a reverse osmosis system increases, so does the system’s cost.

Water source

Homes where water delivery occurs through pipes from a utility provider use reverse osmosis systems, usually from a municipal water source. If you have well water, make sure the reverse osmosis system you are looking at can handle it. 

What to look for in a quality reverse osmosis system

Filtration stages

All reverse osmosis system products use filters to remove pollutants and contaminants. One big difference is how often they filter the incoming water before delivering it to your tap. This happens in a process of three stages or more. 

Reverse osmosis systems with fewer stages combine some activities, while systems with more significant numbers successively contribute to the refinement process. Keep in mind that more stages mean more filters to buy and replace.

Stage 1: The first stage, or pre-filtration stage, removes the most significant contaminants. Active charcoal is the most common stage one material and filters out the largest particles suspended in the water.

Stage 2: Here, water flows through a semi-permeable membrane with tiny pores to filter out contaminants from water at the molecular level. The higher the pressure of your reverse osmosis system, the faster the flow rate. 

Stage 3: This is called the post-filtration stage, where another carbon filter removes whatever chemical tastes are left. Some reverse osmosis systems stop here.

Stage 4: These filters are installed between stages two and three to remove residual sediment to keep it from clogging the stage 3 filters.

Stage 5: Each previous stage has filtered the water more finely until this stage that reintroduces the good minerals filtered out in earlier stages. These include calcium and magnesium. 

Stages 6 and beyond: These are refinements of earlier steps. Each stage adds additional complexity and cost and takes up more room under the sink.  

How much you can expect to spend on a reverse osmosis system

The primary determinant of the price of a reverse osmosis system is the number and type of filters it uses. Expect to pay $150-$200 at the low end and $500 or more at the high end. There are many good choices in the middle ground $200-$400.

Reverse osmosis system FAQ

Why is it called reverse osmosis?

A. In nature, the process of osmosis is the natural transfer of water between cells with semi-permeable membranes. Natural osmosis distributes the pressure equally between cells. The reverse osmosis process turns things around by forcing the water through membranes to remove visible and microscopic particles.

How often do I need to change my reverse osmosis system filters?

A. If you change your filters according to intervals established by the manufacturer, you should be fine. If you use your filtered water more often, you may want to change your filters more frequently. And certainly, check your filters and your system if you notice any changes in the taste of your water.

What are the best reverse osmosis systems to buy?

Top reverse osmosis system

Home Master TMHP HydroPerfection Reverse Osmosis Water Filter System

Home Master TMHP HydroPerfection Reverse Osmosis Water Filter System

What you need to know: This reverse osmosis system is tops in performance, water quality, customer support and ease of installation.

What you’ll love: The remineralization process adds calcium and magnesium during the nine-stage purification process. It is EPA-approved to use UV to kill, inactivate or suppress viruses, bacteria, and fungi.

What you should consider: This is a pricey solution. 

Where to buy: Sold by Amazon

Top reverse osmosis system for the money

NU Aqua Platinum Series Deluxe High Capacity 100GPD 5-Stage Reverse Osmosis System

NU Aqua Platinum Series Deluxe High Capacity 100GPD 5-Stage Reverse Osmosis System

What you need to know: This compact design installs under smaller sinks in one hour.

What you’ll love: The faucet quality is impressive for the price, as are the components. The PPM meter is a bonus. This reverse osmosis system comes with a 5-year warranty and a lifetime guarantee. The DVD makes installation easy.

What you should consider: The design of this system makes the filters harder to change than they should be.

Where to buy: Sold by Amazon

Worth checking out

Brondell Circle Reverse Osmosis System

Brondell Circle Reverse Osmosis System

What you need to know: This system saves water and space for those who have the patience to wait.

What you’ll love: The streamlined design encloses all the separate components in a case that takes up less space than traditional reverse osmosis systems, essential for those with cramped quarters. The four-stage filtration system filters are easy to change.

What you should consider: The flow rate is too slow for some.

Where to buy: Sold by Bed Bath and Beyond


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David Allan Van writes for BestReviews. BestReviews has helped millions of consumers simplify their purchasing decisions, saving them time and money.

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