Reverse Osmosis Water Filters Buyer's Guide
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  We review, analyze and compare the best water filters in the industry including reverse osmosis systems, faucet filters, water distillers, pitcher filters, whole house filters, water softeners, shower filters, bottled waters and more.

Choosing a Water Filter - What You Need to Know...

ro system

There are several details you need to consider before purchasing a drinking water filter:

Best Type of Water Filter:

Of the different types of drinking water filters, most experts agree that a Reverse Osmosis water filter is your best choice. Reverse Osmosis filters remove the widest spectrum of contaminants compared to other types of filters available.


The most important! Since you'll be drinking the water and connecting the water filter system to your water pipes, you don't want to worry about poorly designed systems that may give impure water, break down often, and even flood your home. So ask questions about the quality of the materials used, the workmanship, and warranty. We suggest purchasing systems built in the U.S. using high quality parts.

Maintenance and Filter Changes:

Look for systems where the filters are easy to replace because this will save you tons of money in the long run. Also, the filter change schedule should be around 12 months (long lasting filter), not too short like 4-6 months. Filter prices should be reasonable. Filter size should be industry standard size, so you can get them anywhere. If the filters are "proprietary" sized, then you'll be stuck with the same supplier for future replacements even if they are expensive.

Price, Quality & Service -- What difference does it make? 

Generally, RO systems at the lower price range (below $200) are of lesser quality. We do not recommend them because of their frequent problems and shorter life-span. RO systems at lower prices are always made overseas and mass produced using mostly low quality components that crack and leak easily under pressure and over time. 

Of course, price should not be the only consideration because there are poor quality systems with high price tags. Very much like cars, there is quite a difference in the quality of RO systems although they may look similar or even identical to each other.

Typical problems with lower-priced or lesser quality systems:

- Shorter pre-filter life: 6 months vs. 1 year
- Shorter membrane life: need to replace in 1-2 yrs vs. 5-7 yrs.
- Lower rejection rate and possible brine water seeping into pure water side due to poor quality membrane housings! ----- so water is less pure (filtration is not as effective or thorough, resulting in high TDS readings)
- Leakage at fittings & auto shutoff device
- Poor quality tanks that lose pressure after 1-2 years (plastic tanks)
- Each system is not individually tested (often are mass-imported)
- Usually systems are not built in the USA, not tested by FDA or WQA.
- Cost more to maintain in the long run
- Little or no ongoing technical guidance and support from the supplier.

So what should we look for in an RO system?

- Get a system with good quality parts (U.S. made and certified) and good workmanship (system fits snuggly on sturdy frame, clean neat line connections, no cumbersome dangling lines). It takes both good materials and workmanship to build a long lasting and effective water filter system.

Best number of stages(filters) on a reverse osmosis system:

- Get at least a 5-stage RO system. Systems with fewer stages, like 3-4 stages, are less stable, more problem-prone, and require more frequent filter replacement (every 4-6 months). A good 5-stage RO system allows all the filters to last much longer (12 months on prefilters), and the filtered water's quality is more guaranteed due to the many stages. So you'll save money and time in the long run with good quality 5-stage systems.

Best arrangement of filters in reverse osmosis systems:

- Make sure you have 3 pre-filters (pre-filters are the filters before the reverse osmosis membrane), that consist of -- 2 carbon blocks and 1 sediment filter. Important! The 2 carbon filters should go before the RO membrane (stages 2 & 3) so they can protect the membrane from chlorine exposure damage. Your water's purity depends entirely on the condition of the membrane, so it's critical to protect it properly.

Note: Most 4-stage systems do have 2 carbon filters, but there is only one carbon before the membrane, the second carbon is often put after the membrane. So the membrane is not getting the strong protection it needs. This small detail makes a big difference!

The type of carbon filter is also important. Solid "carbon blocks" are much better than GAC (granular activated carbon) filters, or small "in-line" filters. GAC filters tend to leak carbon powder that clog up the system. "In-line" filters are small so they wear out quickly, thereby exposing the membrane to harmful chlorine. "Carbon block" filters don't leak fines and last the longest.

Also stay away from systems with 2 sediment prefilters. A good RO system needs 2 carbon pre-filters, not 2 sediment pre-filters. Because sediment filters cost less than carbon, some manufacturers substitute the 2nd carbon with a sediment, but this will compromise the membrane's life and your water's quality.

What else should we look for when we shop for a water filter system online?

Besides the filtering system's quality, the supplier's trustworthiness is just as important. You will be using this pure water system for years to come, so you want the supplier to be there for technical support and parts support down the road. Good tech support and customer service are hard to find these days. Also see if they have a good amount of positive customer reviews for their systems.

Many online suppliers today make outrageous claims without valid supports. Be wary of unusually long warranties (5-10 years). Long warranties are often "conditional", meaning you will need to provide proof of "proper system maintenance" to be covered under the warranty, and the warranty may or may not cover your particular problem or parts. So read the fine print.

You can get a feeling on the integrity of the business by:

- See if the website is neatly, logically, and professionally designed with solid and consistent messages and contents.

- Look at the product pictures. Are they clear and sharp images? Fussy or incongruent product pictures may reflect carelessness and haste in the supplier's operating style. Small details can reveal big things.

- See if you can find their warranty policy published on their sites. If a supplier offers an attractive & long warranty, yet you can not find the details on their warranty policy, then it's a doubtful warranty!