Filters vary in price and capabilities, so take time to compare. Some come with a filter capacity indicator to provide a visual indication of the filter life and they automatically shut off when the filter is full. This is a real advantage. Studies show that the lack of a life indicator is a major obstacle to water filter market acceptance. People do not know when to change the filter and therefore do not feel confident their water is clean and safe to drink.

Most filters remove lead, copper, chlorine, zinc and particulates from water passing through them. Filter capacity ranges from 35 gallons to the more common 200 gallons and vary in time to produce one gallon from 2 to 20 minutes. Water purifiers range in price from $30 to $200 and produce filtered water in the range of 5 to 25 cents per gallon.