Photo: Water flowing from a tap
Water bottles and filters can end up in landfills, and take lots of resources to produce and recycle.

Photograph by Péter Gudella/Shutterstock

Environmental Impact

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

  1. 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.
  2. 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.
  3. 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:]
  4. 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.
  5. 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.
  6. Lead, a heavy metal, can cause brain damage and developmental problems in children and adversely affect blood pressure, kidneys, and red blood cells.
  7. 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.
  8. Methyl Tertiary-Butyl Ether (MTBE), a gasoline additive, occasionally leaks into groundwater from underground fuel storage, spills, and stormwater runoff, and may cause cancer.
  9. 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.
  10. 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.
  11. 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.
  12. Radium-266 is a radioactive element usually found around uranium deposits.
  13. 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.

«What to Look For | Usage Tips»


@NatGeoGreen on Twitter


  • change-the-course-dry-co.jpg

    Help Save the Colorado River

    NG's new Change the Course campaign launches. When individuals pledge to use less water in their own lives, our partners carry out restoration work in the Colorado River Basin.

  • National Geographic headquarters in Washington, D.C.

    Sustainability at National Geographic

    The National Geographic Society aims to be an international leader for global conservation and environmental sustainability. Learn more about the Society's green philosophy and initiatives.

Learn More About Freshwater »