No filter will remove every contaminant of concern, but here are the most common types and the major contaminants they can handle.
Carbon-filter models include carafes (pitchers), faucet-mounted models, undersink models (usually require a permanent connection to an existing pipe) and whole-house or point-of-entry systems (usually installed in the basement or outside). Carbon, a porous material, absorbs impurities as the water passes through.
What they remove: lead, PCBs, chlorine byproducts (chloramines and trihalomethanes), certain parasites, radon, pesticides and herbicides, the gasoline additive MTBE, the dry-cleaning solvent trichloroethylene, some volatile organic compounds, some levels of bacteria (such as Cryptosporidium and Giardia) and a small number of pharmaceuticals.
Reverse-osmosis systems push water through a semi-permeable membrane, which acts as an extremely fine filter, and they’re often used in conjunction with carbon filters. However, they waste four to nine gallons of water for every gallon filtered.
What they remove: perchlorate, sulfates, fluoride, industrial chemicals, heavy metals (including lead), chlorine byproducts, chlorides (which make water taste salty) and pharmaceuticals.
Ultraviolet light disinfects water, killing bacteria. Countertop units can be found for under $100, but most whole-house units cost $700 and up for NSF-certified models.
What they remove: bacteria; it is used with carbon filter to remove other contaminants.
Distillers, probably the least practical home method, boil and condense water. While countertop units are available, distillers use lots of electricity, generate excess heat and require regular cleaning. Explore filters or other alternatives to remove your contaminant, or, in a pinch, buy distilled water.
What they remove: heavy metals (including lead), particles, total dissolved solids, microbes, fluoride, lead and mercury.
A Few Facts about Water Filters
- Reverse Osmosis (RO) is an inefficient and ineffective water purification system as it removes healthy minerals from water. It also wastes 2 to 3 gallons of water to produce 1 gallon of purified water.
- Distillation doesn’t remove most of synthetic chemicals such as pesticides, herbicides, and chlorine solutions which have a boiling point that is lower than water. It removes natural minerals in water and uses up to 5 gallons of water to produce 1 gallon of purified water.
- Activated carbon (charcoal) filters remove heavy metals such as copper and lead, carbon-based organic chemicals (impurities), and chlorine. They don’t remove chlorine by-products like THMs (trihalomethanes) and harmful bacteria from water. Brita filters and many water filters found in refrigerators use activated carbon (charcoal).
- Brita Pitcher filters remove about 75% of chlorine and they cost about $300 per year, based on 1000 gallons (400 liters) if you replace the filter as recommended. Brita Faucet filters remove 99% of chlorine and they cost about $250 per year, (based on a usage of 1000 gallons).
- If the filter is not changed regularly, the Brita filter may be HARMFUL as it becomes a breeding ground for bacteria that are trapped in the filter and those bacteria will find their way into your drinking water.
The Brita filter is one of the most widely used filters for homes. If you are using the filter longer than its life, you are drinking worse water than tap water. The filter you thought is the cheapest option to drink clean water may not be the best option at all.