Reverse Osmosis Water Filters

Reverse osmosis for the home is a water purifying method in which tap water is forced through a semi-permeable membrane that prevents bacteria and minerals from passing through to produce a more pure form of drinking water. The choice of a water filtration system depends on if you’re looking to rid of a specific contaminant or if you’re generally looking for cleaner tasting water. For a full description of home water filter choices see our Best Rated Water Filters of 2010.

Advantages of reverse osmosis include removal of a substantial amount of unwanted contaminants including lead, mercury, iron, chloride, and even fluoride. Reverse osmosis is a greener and ultimately more affordable alternative to purchasing bottled water due to waste as well as potential harmful chemicals found in plastic bottles. Also, not all bottled water is treated with reverse osmosis, with many brands containing mere tap water. Though reverse osmosis is more energy efficient than other water filtration systems, one disadvantage is that it uses water to make water with approximately 3-8 gallons of water used to make 1 gallon of pure water. However, it’s still considered an efficient way to get contaminant-free drinking and cooking water in your home. Most systems come with an installation kit and instructions for home installation. The following are our picks for home faucet reverse osmosis water systems.

Watts WP5-50 Premier Five-Stage Manifold Reverse Osmosis Water Treatment System

Watts WP5-50 Premier Five-Stage Manifold Reverse Osmosis Water Treatment System

This under the counter reverse osmosis system by Watts offers 5 stages of filtration. The first stage traps particles such as dirt and sediment. Stages 2 and 3 are both carbon block which is important in removing chlorine from drinking water and will also protect the next filtering stage from the harmful effects of chlorinated water. The fourth stage is the reverse osmosis itself which will remove arsenic, lead, salt, parasitic cysts, and other harmful contaminants. The fifth stage uses a GAC filter which polishes the water as it leaves the tank and makes its’ way up to the included water dispensing faucet. The Watts system uses a 3 gallon water tank and comes with a 3 year limited warranty. The filters last for a year and are replacement filters are reasonably priced at $40.00 Amazon reviewers have given it a 4.5 star rating. This unit is NSF certified.

Sells for $183.68 on Amazon.

Purenex 5 Stage Reverse Osmosis Water Filter System

Purenex 5 Stage Reverse Osmosis Water Filter System

This system sold by Purenex uses the 5 stages of filtration similar to the other under the counter systems. The Purenex refills twice as fast as other systems, making an impressive 100 gallons a day of pure drinking water. The automatic shut-off valve kicks in when the tank is full to prevent excess waste. Comes with a lead-free faucet for water dispensing. High-quality filters are recommended to be changed once a year and are similarly priced at around $40. The Purenex comes with a one year warranty excluding the filters and membrane and is NSF certified.

Sold on Amazon for $155.99.

Watts 500315 Counter-Top Drinking Water Filter

Watts 500315 Counter-Top Drinking Water Filter

In comparison to under-the-sink models, counter-top reverse osmosis filters are less expensive and have the added benefit of being portable. They are easy to install by attaching to the main faucet and sit next to the sink, which frees up space under your cabinet, but do take up that counter space. They don’t have the extensive filtration process as the bigger ones, but they still remove sediment, chlorine, and lead for a cleaner tasting drinking water. You’ll still want to make sure it has a carbon block filter and the the Watts 500315 does, accepting any 10-inch replacement filter, which are inexpensive and only need to be changed out yearly. The Watts has received a 4 out of 5 star rating by Amazon reviewers and is NSF certified.

The Watts 500315 sells on Amazon for $38.84.

Pure Water Products Countertop Model 77

Pure Water Products Countertop Model 77

Pure Waters Products is a company based in Texas who specialize in water filtration. Their counter-top model 77 is their best seller and they’ve been perfecting it since the late 80s. Pure Waters offers a lifetime guarantee and stocks all replacement parts. The model 77 is portable or can be converted to use under the sink. Filters need to be replaced yearly. They also offer a variety of styles and colors. You can also choose between their stainless steel standard gooseneck faucet or a long reach spout. Though it’s not the cheapest or the most expensive, Pure Waters uses high quality components to make what they claim to be the best water filter. All Pure Water Products are NSF certified.

You can order the Pure Water Products Model 77 here.

Countertop Superior Water Filter System

Countertop Superior Water Filter System

The Countertop Superior Water Filter easily installs onto your faucet with a diverter valve and uses a 1 micron carbon block filter which needs to be replaced yearly with standard 10″ filters. One advantage of a clear casing for your filter is you can see what’s being filtered. However, for some, this can also be a disadvantage. Flow rate is .75 gallons per minute. Amazon reviewers have given this model by Superior an average 4.5 stars out of 38 reviews. And as the others, the Superior is NSF certified.

Sells for $43.38 on Amazon.

Ovopur Blanc Water Filter

I’ve been testing an Ovopur water filter from Aquaovo, a company based in Montreal. This filter is certainly the most attractive I’ve come across. My eye is often drawn to its porcelain ovoid shape sitting in my ktichen. I’ve come to think of it as a piece of art that also happens to filter water.The Ovopur operates as a drip filter — you pour water in the upper porcelain chamber, and it drips down through a filter into the lower chamber.

Ovopur Ceramic Water Filter

I enjoy drawing water from this object using the sturdy handle. The main water reservoir holds about 3 gallons (11 liters) – the water level is indicated by magnetic gauge on the side.

The filtration quality it is quite good — the filter incorporates KDF55, activated carbon, microporous bioceramics and quartz crystal.

Ovopur Filter Detail

The Ovopur is also priced like a piece of art, they go for around $850 and replacement filters cost about $160. Aquaovo recommends changing filter cartridges every 4 months to prevent bacteria build up and pollutants overload of the filtration media.

The Ovopur is available from Modern Gadget and Modern Furniture Discount.

See the Aquaovo for more details.

Check out the different color options and configurations below:

Ovopur Caviar Water Filter

Ovobar Caviar Water Dispenser

The Best Water Filters: A Review

There are a lot of misleading claims about water filters. Many filters are marketed with general statements like “improves taste and odor”. But filter manufacturers don’t mention the specific amount of pesticides or chloramines removed, for example. Government websites also tend to leave out important data on water contaminants — it’s not in their interest to point out the problems with municipal water. We’ve found the best reviews of water filters comes from independent experts.

The best books on water purification I’ve found are The Drinking Water Book by Colin Ingram and Don’t Drink The Water by Lono A’o. Ingram suggests that one should first discover which pollutant are in your local water supply. You can then customize your filtration by selecting filters that target those specific pollutants. For example, if are you in a region of the U.S. where radon and uranium is commonly found in the groundwater, choose specific filters to remove those radioactive pollutants.

There are many sources of water contamination (see the graphic below), and sophisticated water purification is simply not possible on the massive scale that municipalities have to deal with.

Potential Sources of Water Contamination

Here’s the list of types of contaminants you want to remove from municipal tap water:

1. Organic compounds (Pesticides, Herbicides, Pharmaceuticals, Fuels, etc.)
2. Toxic metals (Lead, Mercury, Aluminum, Cadmium, Chromium, Copper, etc.)
3. Bacterial and viruses (Giardia, Cryptosporidium, etc.)
4. Radioactive substances (Radon and Uranium, etc.)
5. Additives (Chlorine and Chloramines, Fluoride, etc.)

Ingram’s book also contains a comprehensive collection of water filter reviews. He rates filter from “Acceptable” to “Excellent++”. Here are the ratings:

• Pitcher Filters (Acceptable)
• Faucet Filters (Acceptable)
• Countertop Filters (Good)
• Under-Sink Filters  (Good to Very Good)
• Reverse Osmosis Countertop Purifiers (Good to Very Good)
• Reverse Osmosis Under-Sink Purifiers (Good to Very Good)
• Countertop Distillers (Excellent to Excellent++)
• Whole House Filters (no clear answer, but appears to be mostly “Very Good”)

Notably, all the pitcher-style filters and faucet-mounted filters get a rating of “Acceptable” (the lowest rating).

Countertop Water Filters

There are dozens of brands of countertop filters, and many are made to high manufacturing standards. However, the cost of replacement filters can be high. So countertop filters with standard 10-inch cartridges are recommended. Ingram says: “The availability of a wide variety of standard cartridges allows consumers to customize a water purifier for specific water conditions and to purchase cartridges from a competitive array of suppliers.”

Recommended countertop filters with 10-inch cartridges: Puriteam (formerly Puritech), Superior Water Filter System and Aquatic Reef Countertop.

Puriteam filters are available on their website.

You can purchase others at Amazon.

Under-Sink Water Filters

Under-sink filters tend to tend to have space for two or three different filter types, which is important if you want throughout filtration. Look for those filters that accept standard 10-inch cartridges.

Based on our research, the best performing water filters for your money are:

• The PurHome UCT by Puriteam ($299)
• The Triple Undersink Filter ($199) and the Enhanced Performance Filter by Pure Water Products (starts at $300)

Countertop Reverse Osmosis Purifiers

Reverse Osmosis Countertop Purifier

Countertop reverse-osmosis filters are full-size, multistage systems with performance that approaches or equals that of under-sink reverse osmosis units. Recommend models are Reverse Osmosis Filter by Pure Water Products and TGI CT-445 by Topway Global Inc. These filters have four stages: a sediment filter, a granular carbon filter, an reverse osmosis membrane, and a final granular carbon stage.

Under-Sink Reverse Osmosis Purifiers

Watts Reverse Osmosis Under-Sink Water Filter

There are hundreds of brands of under-sink reverse osmosis systems. Under-sink units generally perform better than counter-top reverse osmosis units, because they employ booster pumps and allow the reverse osmosis membrane to function optimally.

Recommended systems are: Watts Reverse Osmosis Systems, the Enhanced Water Filter by Pure Water Products, Rioflow USR04-50, TGI WIN445, and the Puregen ERO-535.

Gravity-Fed Drip Filters

British Berkefeld Ceramic Drip Filters

If you are looking good filtration on a budget, I recommend a gravity-fed drip water filter system like British Berkefeld. These filters range in price from $200 – $250. They require no electricity to operate — water is filtered as it drips from the upper chamber to the lower chamber. Because the water is filtered slowly, the filtration is much more effective than a faucet-mounted filter. Berkefelds use “candle” type filters, which are widely available and can be customized to your specific filtration needs. Another advantage of this filter is that it can be collapsed and taken with you when you go on vacation.

Available from Amazon, see also the fluoride version.

Countertop Distillers

Countertop distillers are effective water purifiers, but they take some time to distill water (for example 5 hours to distill 1 gallon). They also give off some heat and the integrated fans make some noise.

Countertop distiller that get a rating of “Excellent” are the Megahome Countertop Distiller, Waterwise 4000 and Waterwise 8800, Kenmore 34480 and Pure Water Mini-Classic.

Megahome Countertop Water Distiller

Megahome Countertop Water Distiller / Filter

This distiller is sold under many brand name, and it’s the most widely distributed distiller in the world. It has many quality components despite being inexpensive. It produces 1 gallon of water in 5 hours. The water is passed through a small granular carbon filter. There’s a sealed connections from the distiller to the water collection container, so there is minimal risk of contamination by air. The unit has a stainless steel boiling chamber that is easily accessible for cleaning.

The Megahome Countertop Distiller is available from Amazon for about $150.

Waterwise 4000 Countertop Distiller

Waterwise 4000 Countertop Distiller

This is a more powerful version of the distiller listed above. It has the same features but produces 1 gallon of distilled water in 4 hours. Also received an “Excellent” rating.

The Waterwise 4000 is available from Amazon for about $280.

Waterwise 8800 Water Distiller

Waterwise 8800 Water Distiller

The Waterwise 8800 is an inexpensive high-quality distiller. It produces 1 gallon of water every 4 hours. It received an “Excellent” rating from Ingram.

The Waterwise 8800 is available from Amazon for about $280.

Pure Water Mini-Classic

Pure Water Mini-Classic Distiller

This rugged distiller is built out of stainless steel. It weighs 24 pounds, the filter housing is also made of stainless steel so there’s no contact with plastic.

The Pure Water Mini-Classic is available from Amazon for about $600.

This summer I’ve been working on food-related optimization projects, here are some updates:

I now have subscriptions with two local farmers (through a CSA or Community Support Agriculture). One farmer provides me with raw milk, raw butter and eggs, the other farmer provides vegetables and fruit. They both happen to deliver to same street in my neighborhood, so I ride my bike about one kilometer and pick up both deliveries using a bike trailer.

I bake fresh bread throughout the week using the Artisan Bread in Five Minutes a Day method. This involves creating enough dough for a week, and storing it in the refrigerator. You can take out batches of dough as needed, and cook fresh bread.

I am buying raw (green) organic fair-trade and farm-gate coffees from Sweet Maria’s, and roasting it on my stovetop using a $22 Whirley-Pop Stovetop Popcorn Popper. This makes enough roasted coffee for about two weeks. See the book Home Coffee Roasting: Romance and Revival for more information.

I have been taking all the plastic wraps off my cheese as soon as I get it home. Plastic “suffocates” cheese and traps too much moisture, making the cheese susceptible to mold. I started re-wrapping my cheese in special cheese-wrapping paper, but now I just use wax paper.

I am growing tomatoes and peppers in self-watering containers, and I grow herbs in regular containers since they do not like constant watering.

I’m still investigating different methods of water purification. I came across a useful introductory book on this subject called Don’t Drink The Water: The Essential Guide To Our Contaminated Drinking Water and What You Can Do About It. The author recommends a KDF-Carbon Block Filtration System for household filtration. This combination system get high marks because it is relatively inexpensive and it performs as well as a reverse-osmosis system (but it is much less wasteful).

One of the simplest and most inexpensive ways to purify water is to bubble ozone through it. Ozone is a molecule made of three oxygen atoms ( O₃₎. It disinfects water very effectively, through a process called oxidation. Ozone ruptures the cellular structure of organisms, killing them. It also oxides toxic organic chemicals, minerals and metals by reducing them to their insoluble form, so that they can be filtered out. This means it neutralizes most of the compounds that cause odor and off-tastes. Note, however, that ozonation does not remove nitrates, sulfates or heavy metals (see my article on water filters to find how to remove these).

In Europe and Asia, ozone is used in place of chlorine to purify public drinking water. Ozone is able to oxidize organic contaminants more completely and quickly than chlorine. It is healthier to use than chlorine because ozone does not form chlorine disinfection by-products like THMs. Instead any residual ozone dissolves into oxygen.

To produce ozone in your home, you can purchase a device called a ozone generator or ozonator. Ozonators generate ozone by passing air through a high-frequency electric field. These devices are commonly sold to purify the water in hot tubs and spas.

I’ve been testing an A2Z Ozone Generator. This $70 ozonator uses corona discharge to produce ozone, this involves using an electric discharge brought on by the ionization of a fluid . It produces ozone at a rate of 600 mg/h per hour. The ozone is pushed through a tube, and comes out through a bubbler stone. The ozone it produces smells like fresh, metallic oxygen.

Using this generator you can purify 5 gallons of water in 10 minutes, by placing the bubbler in a container of water. You can also use it your bath or hot tub. Ozone also destroys airborne odors caused by wet carpets, cigarette smoke or basement mold. The federal Occupational Safety and Health Administration (OSHA) has set safety standards for ozone concentration in the air.

For a comprehensive look at all the uses of ozone, see the books Flood Your Body With Oxygen by Ed McCabe, and the The Oxygen Prescription by Nathaniel Altman.

For more information on using ozone for water purification see The Drinking Water Book by Colin Ingram, and Don’t Drink The Water by Lono Kahuna Kupua A’O.

I’ve spent quite a bit of time researching how to filter drinking water effectively. Originally, I was interested in filtering the rainwater that falls on my roof. But I had to put that project on the back burner for now. During my research I noticed that there is little unbiased information available on water filters and filtration techniques.

Update: I discovered a good book on the subject of drinking water filtration: The Drinking Water Book. The author, Colin Ingram, includes a comprehensive collection of water filter reviews. He rates filter from “Acceptable” to “Excellent”. See our review The Best Water Filters Of 2009 for more information.

Waterwise 4000 Countertop Water Distiller

I like clean tasting water, and pure water is quite important to one’s health. Filtering your own water at home is really the most effective way of ensuring good water quality. As you may know, bottled water is extremely inefficient, and tends to be of lower quality than municipal tap water. However, tap water often picks up contaminants on its way through the pipes to your house. But with proper filtering, it can be made quite pure.

There are six types of contaminants you want to remove from municipal tap water:

1. Chlorine and chloramines
2. Volatile Organic Compounds (pesticides, herbicides, etc.)
3. Heavy metals (Lead, Mercury, Aluminum, Cadmium, Chromium, Copper)
4. Bacterial and viruses (Giardia and Cryptosporidium)
5. General Sediment
6. Fluoride

In terms of personal health, chlorine and VOCs are the most toxic contaminants commonly present in municipally treated drinking water.

You can remove most of these contaminants using water filters (except for fluoride and MTBE, but more on that later). There’s really no need for elaborate filtration systems like reverse-osmosis or distillation. These systems are expensive, and they are not needed when filtering tap water, plus they also remove useful minerals from the water and give it a “flat” taste due to the lack of minerals and oxygen. Moreover, the distillation process does not remove VOCs in the water.

There are a lot of water filters out there, and most will do their job reasonable well, but only if they are replaced every six months, and this can be quite costly (I’ll let you know about less expensive filters below). The editors at ConsumerSearch.Com compiled water filter reviews from various magazines, and the consensus seems to be that Pur brand are the best faucet-mount filters and pitcher filters, and Whirlpool has the best whole-house filters.

NSF International certifies water filters — this certification ensures that the filters do their job, and do not re-contaminate the water with bacteria. Most filter manufactures will advertise that their filters are NSF certified. However, many commonly available filters will let quite a few contaminants through. For example, granular filters do not utilize the chemical adsorption process, allowing several contaminants to pass through. Likewise, rapid water filters do not give the water adequate contact time with the filter media, limiting the number of contaminants that may be removed. For example, in-fridge or faucet-mount filters may not filter VOCs and chlorination by-products like Trihalomethanes (THMs). Generally, slow filtration tends to be best. Drip filters will remove a wider range chemicals, pesticides and MTBE (a gasoline additive).

In my home, I use a British Berkefeld drip filter, which is made by Doulton (pictured above). I like drip filters because they provide great quality filtration, and they are inexpensive to use, because they only need to be replace every six months. You can clean them with a stiff brush if they become dirty with sediment. To use a drip filter, you pour tap water in the top, and the water slowly drips through the filter to the bottom compartment. The process takes a couple of hours.

My Berkefeld drip filter contains two SuperSterasyl self-sterilizing ceramic elements. The elements are made with diatomaceous earth (a silica-like sediment originating from kiesel algae), silver and activated carbon. It’s important to have self-sterilizing elements because they can easily become contaminated with bacterial, especially while cleaning them. The sterilization is achieved by impregnating the filter with silver.

Another good ceramic drip filter is made by Stefani (pictured above). I like their French Provence inspired design. The filters are manufactured in Brazil, and the units are hand made by local clay potters. The clay cools the water, due to an evaporative cooling effect. These filter remove 95% of chlorine, pesticides, iron, aluminium and lead; and 99% of cryptosporidium, guardia and sediment. The filters lasts six months or 300 gallons. Stefani filters are available at Amazon.

Let’s address some the contaminants that can only be removed using specialties filters: fluoride, arsenic, and MTBE. These special filters are typically added in series to a standard water filter.

Fluoride is commonly added to municipal water in the U.S. The reason given is that it supposedly improves the health of children’s teeth. However, many people (including me) would rather not have fluoride in their drinking water, for a variety of health reasons. The Fluoride Action Network has a lot of relevant information on this topic. Fluoride is actually quite difficult to remove from water, almost all water filters will not remove it. It can be removed with an “activated alumina” filter. Doulton and other companies offer activated alumina filters.

MTBE (a gasoline additive) has contaminated much of the groundwater in the U.S. In drinking water, even trace amounts of MTBE can cause taste and odor problems. The potential long-term health effects of MTBE are not understood at this time, however, initial studies indicate MTBE may cause kidney and liver problems. You can remove MTBE using a specialty filter, for example this one.

Arsenic is another common contaminant that can only be removed at significant levels using a specialty filter. For more information about arsenic in drinking water see this page. Filtration through activated carbon (which many water filters use) will reduce the amount of arsenic in drinking water from 40 – 70%. Anion exchange filters can reduce it by 90 – 100%

More information can be found in The Drinking Water Book.

This is a serious portable water filter from Katadyn. It’s efficient because it uses a ceramic filter, which will not let anything larger than 0.2 microns through. It also has a long life — it will filter up to 13,000 gallons before you need to replace the cartridge. The filter eliminates bacteria, viruses, cysts, protozoa, algae, spores, sediment and reduces radioactive particles.

Home page: Katadyn

Available from Amazon for $189.

Here is another efficient ceramic water filter. This gravity filter has a hand-made terra cotta base, which cools the water using natural convention.

We consider metaefficient because: its has excellent filtration, and a very long filter life (years). Also, the terra cotta doesn’t leach contaminants into the water, and it keeps the water cool without needing external energy.

It’s available from Water Savers for $139.

See also these similar ones on Ebay: ceramic filter and gravity filters.

Gravity filters are more effective than other types of water filter, because the water drips slowly through the ceramic elements, and this process removes almost all the contaminants in water. The filters can be cleaned with a toothbrush and last for up to 2,000 gallons. This Berkey Light filter uses Black Berkey elements, and they are self-sterilizing. The Black Berkeys remove or reduce pathogenic cysts, parasites, harmful or unwanted chemicals such as herbicides and pesticides, VOC’s, SOC’s detergents, organic solvents, trihalomethanes, cloudiness, silt, sediment, nitrates, nitrites, heavy metals, foul tastes and odors. Yet they leave in beneficial minerals.

Available from H20 Filters for about $170.

Slow sand filters are perhaps the most efficient means of producing clean drinking water.

Slow sand filters rely on biological processes for their action rather than physical filtration or disinfection. They require no electricity, no chemicals and no filter changes.

How is this possible? The secret is that slow sand filters work through the formation of a gelatinous layer called the hypogeal layer or “Schmutzedecke” on top of a layer of fine sand. This layer consists of bacteria, fungi, protozoa, rotifera and a range of aquatic insect larvae. As a Schmutzedecke ages more algae tend to develop and larger aquatic organisms may be present including some Endoprocta, Snails and Annelid worms.

The Schmutzedecke is the layer that provides the purification for water treatment — the underlying sand provides the support medium for this biological layer. As water passes through the Schmutzedecke, particles of foreign matter are trapped in the mucilaginous matrix and dissolved organic material is adsorbed and metabolized by the bacteria fungi and protozoa.

The water draining from a well managed slow sand filter can be of exceptionally good quality with no detectable bacterial content.

Blackburn and Associates produce a slow sand filters for residental use.