Rainwater Harvesting Online Calculator

Name: Spring 2020 – Permaculture Design Course, Tucson, AZ
Start: 2020-02-08T09:00:00-08:00
End: 2020-02-08T09:00:00-08:00

BALANCING YOUR ON-SITE WATER BUDGET FOR YOUR LANDSCAPE in Southern Arizona

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.

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)

Graywater-Source Appliances Note: Greywater is not an additional water income if you have a stand alone rainwater harvesting system where rainwater is your only water source. In this case, graywater is just another cycling stage of that rainwater.
	# of people in household
	Top-loading washing machine (assumes 35 gallons per load), loads per week
	Front-loading washing machine (assumes 10 gallons per load), loads per week
	# Showers per person per week (assumes 5 minute shower)
	# Baths per person per week (assumes 40 gallon bath)
	# minutes faucet run per person per day
	AC unit (enter "1")
	Swamp cooler (enter "1")

Quantity
	Citrus (edible or ornamental)
	Dwarf citrus tree
	Velvet mesquite
	Screwbean mesquite
	Native Acacia or Palo Verde
	Oleander
	Native deciduous 5' shrub
	Native evergreen 5' shrub
	Pomegranate
	Mission Fig
	Additional plants at gallons per month (see Appendix 4 of Rainwater Harvesting for Drylands and Beyond, Volume 1)
Square Feet
	Vegetable garden
	Bermuda grass turf

Your roof harvests:	(see note)
Consider sizing a rainwater storage system for your property that holds at least:
Your available water resources are:
Your current outdoor water needs are:	(see note)
Your net monthly water budget is: