Rainwater Harvesting for Drylands and Beyond by Brad Lancaster

Rainwater Harvesting Online Calculator


The goal is to use on-site non-potable water for your landscape instead of high-cost, imported potable (municipal/well) water.
Begin by entering values for the items below.

Water Income

Fill in the blanks below to determine how much rainwater and greywater can provide for your landscape.
Roof-Harvested Rainwater
Square feet of roof space (help)
Your site's average annual rainfall in inches (Bisbee - 20.7", Nogales - 19", Patagonia 17.78", Phoenix 7.40", Sierra Vista 14.24", Tucson -11.56", Wilcox - 13.4", Yuma - 3")
Where can I find this info? (opens in new window)
Check which applies to your site:
Rainwater is one of my water sources (others may be municipal water, well water, trucked in water, spring water. If one of those non-rainwater sources is your domestic water source for sinks, washing machine, and/or bath/shower, then the resulting greywater is counted as additional non-potable water income for use in the landscape)
Rainwater is my only source of water (in this case greywater is not counted as an additional water income or an expense, but an additional cycle/use of that rainwater if used to irrigate plantings)

Drops in a Bucket Blog

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Upcoming Events

Also see the full list of upcoming events.

Umbrella Newsletter

The Umbrella: Spring Equinox 2017

A catch-all of resources,
events, media, and more
from Brad Lancaster
Spring Equinox 2017
Around here we like to rhyme with the seasons whenever possible. In this case, that means welcoming the fast-approaching beginning of SPRING (the Vernal Equinox (in the northern hemisphere) is March 20 this year in Tucson, and marks one of only two […]

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