Municipal water supplies do not all have the same effect on plants. Water source, geological history of the area, local mandates and city water treatment facilities all influence what comes out of the tap in the kitchen or garden.
All water comes from the water cycle: from watersheds, reservoirs or artesian wells. It returns to the cycle through aquifers or watersheds. City water and water from a private well near the city often use same source.
Water travels through rock layers in the aquifer. Arsenic, carbonates, iron, copper and other chemicals and minerals are part of rocks. Bacteria and viruses that occur in the environment may also be present in the aquifer.
Cities filter water to remove physical impurities. They add "disinfectants," usually chlorine, to kill bacteria. Some cities use ozone or chloramines; a growing number are using reverse osmosis or activated charcoal to disinfect water.
Beneficial minerals may be removed in the purification process. Disinfectants create compounds including bromates, chlorites, chloromines and chlorine dioxide that are toxic to plants.
Gardeners should find out what disinfectants are used in their city's water. They may need to let water sit overnight to allow chlorine to evaporate before using it on plants.
- U.S. Environmental Protection Agency: Drinking Water Contaminants
- Wisconsin Department of Natural Resources: 96 Percent of Public Systems Meet Standards
- New York State Department of Health:Wastewater Treatment Standards
- U.S. Environmental Protection Agency: The History of Water Treatment
- U.S. Environmental Protection Agency: Arsenic in Drinking Water
- U.S. Environmental Protection Agency: Primer for Municipal Wastewater Treatment Systems
city water, municipal water treatment, water and plants
About this Author
Chicago native Laura Reynolds has been writing for 40 years. She attended American University (D.C.), Northern Illinois University and University of Illinois Chicago and has a B.S. in communications (theater). Originally a secondary school communications and history teacher, she's written one book and edited several others. She has 30 years of experience as a local official, including service as a municipal judge.