With all of the rain we have been having lately, it is hard to imagine that we would need to conserve. Rainwater catchment systems at home can go a long way to conserving our water here in Hawaii.

Patricia Macomber, from the Department of Natural Resources and Environmental Management at the College of Tropical Agriculture and Human Resources at the University of Hawaii at Manoa, wrote the manual on guidelines for rainwater catchment systems for Hawaii. According to Macomber, an estimated 30,000 to 60,000 people in the state are dependent on rainwater catchments for their water needs. She offered these tips for building or maintaining a system of your own:

Look around the roof. If you are planning to catch the rain from the gutters, make sure that trees and shrubs surrounding your home are not touching or hanging over the roof. Not only can the debris block rain from getting to the tank, but the plants can host insects, birds and rodents whose waste can contaminate your supply.

Assess your materials. For the catchment system itself, Macomber suggested using materials that are nontoxic and non-leaching. She pointed to the acid rain in Hawaii as cause for increased probability of chemicals leaching from the materials the water touches.
Add screens. One of the best ways to keep large debris out of the system is to put screens over your gutters. Macomber advised placing screens at an angle so that leaves and other debris can slide off.

Go down. Another source for water pollution is stagnant water. Downspouts, which carry the water from the gutter to the storage tank, should have a continuous downward slope from roof to tank, said Macomber.

Take care of the cover. Tank covers can sometimes sag and result in pooling. This acts as an invitation for birds and other animals to take a drink and for mosquitoes and other insects to use the space for breeding.

To learn more, take a look at Macomber’s full manual of guidelines. You can also consult the Board of Water Supply.

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