How To Chose A Water Filter
A recent investigation by The New York Times found that, since 2004, some 62 million people in the U.S. have been exposed to drinking water contaminated with thousands of chemicals—albeit in low concentrations—that are not regulated under federal law.
Of course, the best way to ensure clean and safe drinking water is to protect the source. Watersheds act as natural filters that remove chemicals, pollutants, and sediment. Citizens can also urge Congress and the federal government to update the Safe Drinking Water Act to include and regulate potentially hazardous new chemicals.
In the meantime, many consumers are turning to home water filters for added peace of mind.
The first step in determining whether a water filter might make your tap water cleaner is to find out what’s in your water, and if it contains any dangerous, unregulated chemicals.
If possible, check out your annual water-quality report—also called a consumer-confidence report—from your water supplier. Some reports are available on the U.S. Environmental Protection Agency (EPA)’s Web site. These reports can be difficult to interpret, so download a guide to reading them at the Campaign for Safe and Affordable Drinking Water’s Web site.
The Environmental Working Group’s “What’s in your water?” tool is another useful mine of information on local water supplies. The nonprofit recommends that most people in the U.S. filter their tap water.
If you decide to purchase a water filter, experts recommend selecting filters certified by the National Sanitation Foundation, which tests products to ensure that they remove what is required by water-filter manufacturers.
The foundation maintains an extensive database searchable by type of water treatment product.
No filter will remove every contaminant, in part because the list of risky chemicals keeps growing. But here are the most common types of filters and the major contaminants they are designed to trap:
- Carbon filters include countertop pitchers, faucet-mounted models, undersink models (which 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 semipermeable membrane, which acts as an extremely fine filter. They’re often used in conjunction with carbon filters. However, these systems waste 4 to 9 gallons (15 to 34 liters) of water for every gallon (3.8 liters) filtered. What they remove: Chemicals carbon filters may miss, including perchlorate, sulfates, fluoride, industrial chemicals, heavy metals (including lead), chlorine byproducts, chlorides (which make water taste salty), and pharmaceuticals.
- Ultraviolet light units disinfect water, killing bacteria. Countertop units can be found for under U.S. $100, but most whole-house units cost $700 and upward. What they remove: Bacteria. Experts recommend using them with carbon filters 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 contaminants, or, in a pinch, buy distilled water. What they remove: Heavy metals (including lead), particles, total dissolved solids, microbes, fluoride, lead, and mercury.
Most U.S. citizens count on their local governments to ensure that their water is clean and safe. And with daily, mandatory testing, municipal water is actually more regulated than bottled water, which is usually only tested annually.
Nevertheless, problems with municipal supplies, convenience, and simply good marketing has led many consumers to choose bottled water over tap water. But bottled water is associated with an array of environmental concerns, including the generation of billions of wasteful plastic bottles, the burning fossil fuels to refrigerate and transport those bottles, and the draining of aquifers and watersheds to fill the bottles.
At the same time, used water filters—often housed in plastic casings—aren’t recycled either. So test your water before investing in plastic filters that will ultimately get tossed in a landfill.
Human Health Issues
Water filters remove common contaminants in city water supplies, ranging from the minor (taste and odor problems) to the serious (cancer-causing pesticides and pharmaceuticals that can contribute to bacterial resistance). Here are some of the most common chemicals found in city water:
13 Common Water Contaminants
- Alachlor is a potentially cancer-causing herbicide applied to corn, soy, and sorghum crops in the U.S. Midwest that can run off from fields into drinking water sources.
- Arsenic, a naturally occurring poison that can also cause cancer, is found in all 50 U.S. states, often in wells. Higher levels are found in the Southwest.
- Atrazine, a widely used pesticide, may cause hormone disruption, cancer, weight loss, muscular degeneration, and cardiovascular damage. Found in all 50 states, it’s most common in the Mississippi River Basin during spring runoff periods. [could link to: http://news.nationalgeographic.com/news/2010/02/100301-atrazine-frogs-female-chemical/]
- Benzene is a known carcinogenic chemical emitted by the petroleum and chemical industries. It can taint drinking water via air pollution, leaking underground gas storage tanks, industrial discharges, and poor waste disposal.
- Chromium is a heavy metal typically pollutes drinking water via discharge from steel and pulp mills and erosion of natural deposits. In various forms it can affect the respiratory system, digestive tract, and circulatory system, among others.
- Lead, a heavy metal, can cause brain damage and developmental problems in children and adversely affect blood pressure, kidneys, and red blood cells.
- Mercury, another heavy metal is produced in some industrial facilities; during coal burning, landfill, and agricultural runoff; and erosion of mineral deposits. Methylmercury, an organic compound of mercury, is a known human neurotoxin linked to harmful health effects in people, especially children.
- Methyl Tertiary-Butyl Ether (MTBE), a gasoline additive, occasionally leaks into groundwater from underground fuel storage, spills, and stormwater runoff, and may cause cancer.
- Nitrate, which comes from animal waste in dairies, on cattle farms, and on feedlots, can cause “blue bay syndrome,“ which prevents blood from holding oxygen. It’s more common in rural areas.
- Pathogens such as Cryptosporidium, E. coli, and Giardia, carried by animal and human waste, are linked to gastrointestinal illnesses. Cryptosporidium infection can be life-threatening for people with weakened immune systems.
- Perchlorate, a contaminant from rocket fuel production, has leaked into U.S. drinking water due in part to improper disposal. The chemical harms the thyroid and may cause cancer. Currently, there is no EPA standard for perchlorate, but its risks are being assessed.
- Radium-266 is a radioactive element usually found around uranium deposits.
- Trihalomethanes (THMs), a byproduct of chlorine treatment, are linked to cancer, miscarriages, and birth defects.
For more information, see the Natural Resources Defense Council’s report, which lists more than 30 drinking-water contaminants and their effects on health. Also visit EWG’s water-filter buying guide.