America's water supply is supposed to be safe to drink straight from the tap, but it looks like many Americans do not believe this. Which is why there is a big and growing market for bottled water and home water filters. If you browse the shelves of your local Target, you will find a large selection of water dispensers, water pitchers and water filters - such a dizzying array you won't know where to start. That is why many consumers looking for home water filtration start from either recommendations (their friends tell them brand XXX produce the best tasting water) or price (Which is the cheapest? The most expensive must be the best, right?).

Unfortunately, these approaches miss the main point - why do you want to buy a water dispenser or home water filter?

  • Do you really not trust the safety of the water from your taps?
  • Or do you just not like the taste of your tap water?
  • Or is it because your tap water has sedimentation and you do not like this?

The above are the three most common reasons why Americans do not want to get their drinking water straight from their taps. They are all valid reasons and require different approaches to selecting the best home water filtration system.

When choosing a water dispenser, there are two additional factors you should consider:
  • Many newer and larger refrigerators actually come with a water dispenser which filters water. Just install the proper water filter cartridge and you will get near instant cold purified water to drink.
  • What is your water quality like? Is there sedimentation? Rust? Is there a strong chlorine smell? Are there significant reasons to believe there is heavy metal contamination, e.g. your plumbing uses lead, copper, brass or bronze pipes/fittings/solder? Is there a strong risk that your water is contaminated by agricultural products like fertilizers, herbicides or pesticides, etc?

Let us take the extreme case of a person living in a long-established agricultural community where his water supply is actually sourced from an artesian well or aquifer. In this situation, there is a large possibility of nitrate or nitrite fertilizers as well as various herbicides and pesticides leaking into his groundwater. There is also the possibility of bacteria like e. coli contaminating his water. Since he is living in an old community, it is very likely that some of the water pipes from the water treatment plant leading to his house is made from lead or uses lead solder. Furthermore, if he is living in an old farmhouse, there is also the possibility of lead or copper from his plumbing. What kind of home water filter should he install?

To ensure the safety of his family, he should install a whole house multi-stage reverse osmosis home water filter as well as point-of-use water filters with resin ion exchange on every tap and shower in his home. Those are a lot of big words, aren't they? Let's break things down into easier-to-digest chunks.

A whole house water filter is a device that is installed between the municipal water supply and our farmer's home plumbing. It gets rid of the nasty stuff from the water supply before the water goes through the pipes in his home. "Multi-stage" means that his water is filtered in several steps:
  • The first step is usually a coarse filter (ceramic filters are usually the cheapest and most rugged) to get rid of coarse sediment.
  • Then there should also be a second step with a fine-grained filter to get rid of small sediment. Some home water filters use ceramic again (more expensive to buy the filtration system, but cheaper to maintain in the long run) or carbon (saves one step, so is cheaper to buy, but usually more expensive to maintain). If there is a lot of sedimentation, the second stage filter should definitely be ceramic to reduce the cost of replacing the water filter cartridges - carbon water filters are more expensive than ceramic water filters.
  • If the second stage is a ceramic filter, the third stage will be a carbon filter. Whether it appears in the second or third stage, the carbon filter will remove the chlorine, herbicides and pesticides in your water. The chlorine removal that occurs in this stage is vital - it helps to lengthen the life of the reverse osmosis filter which rots in the presence of chlorinated water.
  • The fourth stage - reverse osmosis - is the most powerful. It removes any leftover herbicides and pesticides, heavy metals like lead, fertilizers as well as any microorganisms or bacteria that survived the chlorine treatment.

At this stage, his water would be safe to drink, if not for the lead pipes in his home plumbing. That's where the point-of-use (POU) filters with resin ion exchange come in. POU simply means that the water filter is mounted wherever is is needed. In this case, our theoretical farmer would mount a relatively cheap POU water filter on every tap/faucet where he gets drinking water or water for brushing his teeth and gargling his mouth. He should also mount water filters for his showers and bath tubs to prevent absorbtion of dissolved lead and copper through his skin. Resin ion exchange is actually a system which gets rid of heavy metals in the water. It is cheaper than RO (reverse osmosis) which removes all metals, but must specifically target the heavy metals you want to remove. So a resin ion exchange system which is specified to remove lead will only remove lead. Any copper in his water will get through. If it is specified to remove mercury, but there is no mercury contamination in his water supply, that ability is wasted and he is paying an extra and unneeded cost. The more metals this type of water filtration targets, the more expensive it is.

With such extensive home water filtration installed, our farmer's water is now absolutely safe to drink. Of course, if he were even more paranoid, he might still want to boil his water before drinking it. Now, such a complete system of home water filters is sheer overkill for a young urban couple living in an relatively new apartment. Let us assume they have all the usual home appliances, including a refrigerator with a filtered water dispenser. All they would need is to get the right water filter cartridge for their fridge water dispenser.

If they had spare cash and don't know how safe their water supply is, they may want to splurge on the highest-end cartridge recommended for their refrigerator. This includes a fine-grained carbon filter to get rid of chlorine, sediments and the two most common microorganisms in American water supplies, Giardia and Cryptosporidium. There should also be a resin ion exchange unit often targeting lead, but sometimes also targeting mercury and/or copper. There is often also a sediment pre-filter to get rid of coarser sediment and extend the lifespan of the carbon filter.

If our young couple drink a lot of water, they may also want to get a large (18-cup) PUR or Brita water pitcher. These are water dispensers fitted with water filter cartridges to get rid of contaminants. Both PUR and Brita also make OEM filters for the refrigerator-mounted water dispensers, so they can buy cartridges with the same rating (although the shapes and sizes may be different). Should their water supply have a lot of sedimentation, they may also want to install a faucet/tap mounted water filter like Culligan's. These are a poor second place to Everpure's H-300 home water filter, but very cheap and more than adequate when there is already a fridge-mounted water dispenser with its own good quality water filtration.

On the other hand, a prototypical poor college student staying in a dorm may want to get one or two medium PUR water pitchers which he can refill from the taps in his dormitory pantry or toilets. Water pitchers usually work quite slowly, sometimes only purifying one or two cups of clean water after one whole night. If he only has one pitcher, he may need to wait one or two days for clean water every time he cleans the water pitcher. Add an electric kettle and he will always have clean hot water for the late night coffee he needs to stay awake.

This is the kind of analysis you need to do when selecting a home water filter. At one extreme where you have a highly contaminated water supply, you may need very expensive, costly and complete multi-stage reverse osmosis home water filtration. But for the typical urbanite, you can get by with a relatively economical combination of home water filters. And a poor student could easily get by with the bare minimum.