Rainwater Catchment Components
An estimated 30,000 to 60,000 people in the state of Hawai‘i are dependent on a rainwater catchment system for their water needs. The majority of those people are located on the island of Hawai‘i in the Puna, Ka‘ū, and Hāmākua districts. With proper design, maintenance, and water treatment, a rainwater catchment system can provide water that is relatively free of contamination, soft, clear, and odorless; this water can be used for drinking, bathing, washing, flushing, laundry, and gardening. If the system is not properly designed and maintained, it can be a source of serious health risk and illness. It is very important that those using water from a rainwater catchment system understand all of the potential dangers. In Hawai‘i, there are no government agencies overseeing the safety of your catchment system. It is up to you as the owner or user of the system to know how to maintain the water source and use it in a manner appropriate for yourself and your family.
It is important to clean the water-storage tank periodically to remove any sludge that has built up on the bottom. Federal guidelines suggest that water storage tanks be cleaned every three years. You may want to do it more often if the tank gets dirty or less often if you have a closed system with good screening devices and little dust. All tanks build up sludge, but the amount depends on the system and what gets washed into the tank. If you drain the system, do not release the water in an area where it could harm the environment or cause property damage. The reason it is important to clean the sludge and organic material out of your tank is because it is an environment in which microorganisms grow. Also, lead and heavy metals can accumulate in sludge and create a health hazard.
credit: Patricia S. H. Macomber Department of Natural Resources and Environmental Management College of Tropical Agriculture and Human Resources, University of Hawai‘i at Mānoa
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