Anion Exchange

Used to trap and replace negatively charged ions, such as nitrates, perchlorate, fluoride, radium, ammonia and arsenic.

Cons

• Flow rate limited (some others are less than 0.5 gpm)
• Capacity limited for some ions
• Selectivity can be a problem (competition)
• Dumping of contaminant or resin can be a problem if resin is “spent”
• Requires a strong chemical to recharge (sodium hydroxide)

pH Adjustment

Tap water passes through chambers with electrodes to split water molecules into ions. End users are able to select the pH desired.

Cons

• Scientific data doesn’t support claims of being better for skin or digestive health
• Has a waste stream
• Cannot effectively reduce chlorine, organic or inorganic contaminants
• Complex with electronics

Ozone Disinfection

Ozone gas is generated with UV light and bubbled through water.

Cons

• Can create undesirable by-products like bromate or formaldehyde
• Requires electricity
• Does not reduce inorganic compounds

Distillation

Water is heated until it turns into steam. The vapor is then cooled and condensed back into liquid water.

Cons

• Reduces beneficial minerals
• Requires a lot of energy
• Might give water a flat taste
• Might be slow, inconvenient and expensive
• Does not remove low-boiling-point organics

Reverse Osmosis

Pressurized water is forced through a semipermeable membrane, collected in a storage tank and dispensed with a separate faucet.

Cons

• Requires high water pressure (>40 psi)
• Removes beneficial minerals
• Might not effectively remove bacteria and viruses
• Wastes water (typically 80%)
• Might not remove some low-molecular-weight organic compounds

Boiling

Water is boiled for 20 minutes, then cooled to drinking temperature.

Cons

• Does not reduce particulates or many organic and inorganic compounds
• Will not improve water taste, color or odor
• Inconvenient and time-consuming