EPA Water Filtration Recommendations for the Home

The EPA regulates tap water through standards designed to protect water quality, taste, color and clarity. Public systems treat water with chlorine disinfectants and filters in order to meet these standards. However, some people with weakened immune systems require water quality that exceeds EPA standards.

Water Treatment Goals

• In order to choose the most appropriate water treatment system for your home you need to identify treatment goals. Do you want to improve the taste of your water? Is there a family member with a serious health condition that requires very clean water? Do you have a specific contaminant that you would like to treat, perhaps lead getting into your water from older pipes? Once you have targeted goals, specific treatment systems can be selected.

Water Treatment Locations

• Water treatment can occur at various points around your home. Free-standing pitchers filter smaller quantities of water. You can attach filters to individual taps to treat water as it flows through the faucet. You can also attach filters to your refrigerator water and ice connection. Specialized plumbing can be directed to a single faucet, also known as a "point of use" device. Or, central piping leading into the house can treat and provide water to your entire home with a "point of entry" device.

Filtration systems

• Filters use granulated activated carbon and resins which attach to and trap contaminants as they pass through the filters. The microscopic pore size of the filter screen determines what contaminants can be removed. It is important that you analyze screen pore size by largest hole size, not average. Filters by themselves cannot remove all contaminants.
  Distillers heat water to boiling and collect and recondense the vapor to remove the disease-causing microbes and contaminants. Taste is affected because natural minerals and dissolved oxygen are also removed along with the microbes.
  Reverse osmosis units contain semi-permeable membranes which operate under pressure to clean water. These units use three times the amount of water as clean water produced but eliminate all disease-causing organisms and most chemical contaminants.
  Aerators pass water over air jets to force gasoline and radon contaminants to convert to gaseous emissions that are removed.
  Water softeners use basic cation exchange principles where minerals that cause hardness, calcium and magnesium, are exchanged with sodium and potassium, the softeners. At the same time, radium and barium contaminants are removed.

Cryptosporidium

• Anyone with a weakened immune system is highly susceptible to the parasite cryptosporidium, which originates in animal and human digestive tracts, gets into surface water via fecal waste and ends up in drinking water because it is not easily treated with chlorine. The best removal system for crypstoporidium is a reverse osmosis unit labeled as containing a filter with the largest pore size in the screen of one micron.

EPA Registration

• EPA registers water filters but that does not mean it endorses the filter. EPA registers any product that contains germ-killing agents or agents that slow the growth of bacteria. The registration number means that the filter contains these agents but filters must be changed regularly to continue to function properly. Any filtration system requires maintenance, whether it is a free-standing pitcher or point of use plumbing system, the cost of which must be considered when making the initial treatment system purchase.

Water Safety

• Tap water is generally safe to drink. Flooding and other intense weather events may affect the water supply temporarily. Under these circumstances, boiling water for one minute will kill microbes and some contaminants will be removed via the steam. Anyone with compromised immune systems should use filtration systems. Bottled water may still present microbe problems but well and spring water are less likely to contain problematic micro-organisms.