discuss collecting and reusing rainwater.
You might ask, what do you need to store and use rainwater?
The simple answer is a Rain barrel and a watering can. It can also mean something larger with
increased capacity, connected to an automated distribution system.
What kind of system do I need and what can I afford?
The answer to that question will
take some math, the formulas are not hard to work out, collect the data and see the results.
The table below lists some of
the items you will need to measure;
A. Measure your property and determine the square footage 50x150=7500sg ft
B. Measure your house and determine
the square footage 30 x40= 1200sg ft
C. Measure your garage and determine square footage
20 x22= 440sg ft
D. Measure your driveway and determine square footage 10 x120=
E. Measure your sidewalks and
determine square footage 3 x 50= 150sg ft
F. Measure your patios and determine square
footage 10 x 30 = 300sg ft
G. Measure no water areas and determine square
footage 5 x 50= 250sg ft
H. Determine square feet of lawn area to be
watered 50 x 60= 3000sg ft
I. Determine square feet of garden areas
to be watered 30 x 32 = 960sg ft
The requirements for watering
lawn areas, trees and plants are different; approximately 1” of rain is needed weekly on average.
For every 1000
square feet of area that receives 1” of rain, approximately 625 gallons of water hits the ground.
The spigot of an average home
dispenses 5 to 7 gallons per minute, 300 to 420 gallons per hour, water for 2 hours and thats 600 to 840 gallons,
which adds up to 1800 to 2520 gallons when you water 3 times per week, during a typical 30-week growing season 54000
to 75600 gallons.
As you can see a 2-gallon per minute difference in flow adds up to a large difference over
Now it is time
to use some of the figures from the table above.
A = the total area in square feet of your property
50 x 150 = 7500 sq ft
A / 1000 x 625 = gallons of water per 1” rain 7500
/ 1000 x 625 = 4,687.50 gal
That right almost 47 hundred gallons of water hits this property
in a 1” rainstorm.
This checks to make sure the total
area matches the individual areas measured
A-(B+C+D+E+F+G) = (H+I)
to make sure the total area –(house+) = area to be watered.
area to water
7500 - 3540 = 3960 sq ft
(H+ I) = area to water
3960 sq ft
Area to water
/ 1000 X 625 = water needs 3960 / 1000 X 625 = 2475 gal
Water needs per week
= 2475 gal
per week x 30 weeks
= 74,250 gal
should notice the 30-week totals for watering with a hose and the 30 week water needs totals are close, you will also notice
at 5-gallons per minute you will need to water longer to supply enough water for your lawn and garden. These figures
are only examples, each yard will have different needs, based on the climate, ratio of lawn to garden, how much shade covers
your yard and how much water the trees, plants and planters actually require.