The most precious resource in today’s world is potable drinking water. Without water, we can’t survive and we are wasting more and more of it every day. Between increased populations and industrial usage, we are running out.
Living off-grid doesn’t protect you from lack of resources. It amplifies your need to be self-reliant. Especially in the desert, water becomes the most important resource. Control your own water, and you control your own way of life.
For those of you not from New Mexico, we get all our rain for the year in August. This means our system has to be able to make that water last the entire year for us, our animals, our plants, and daily usage.
Every drop has to count.
The first step in planning for your water system is calculating how much water you’re going to need. So lets start with consumption.
Each human should drink about 1 Gal per day.
That doesn’t count washing, cooking, cleaning, etc.
So we put each human consumption at 5Gal per day.
Dairy cows need a lot of water to produce milk and healthy offspring. 20 Gal/day.
Pigs need 3 Gal, and
10 chickens use 2 Gal/day total.
Then I plan out where each one will get its water.
The chicken coop will collect rainwater, as will the home, garage, barn, and sheds. If I have each of these collect and go to a different consumer, then I can produce enough water to take care of everyone happily.
Per year I need:
1825 Gal water per person.
7300 Gal water per cow
1095 Gal water per pig
730 Gal water per 10 chickens.
The Water catchment formula calculates how much water is collected by a surface based on the annual precipitation rate and the square footage of the roof.
Water = Sq Ft of roof X Rain per year X 0.623
For New Mexico, I get about 15inches per year.
If I want to calculate minimum sq footage needed, I simply change the water catchment formula to:
Sq Ft of roof = Water Needed
Rainfall X 0.623
Then I plug my annual rainfall to calculate how much surface I need to get the water necessary for each animal.
Example: Chicken Coop. Needs 730 Gal/year
SqFt = 730
Chicken coop roof needs to be at least 78sqft to collect enough water for 10 hens. So now I plan a 100sqft chicken coop with an overhang roof. This gives me a 150sf surface area to collect rainwater on.
1401 Gal Water = 150sf X 15” rain X 0.623
This gives me double the water necessary to raise my 10 hens.
To get a 150sf roof, I know my coop/chicken run (shaded because New Mexico sun is crazy) needs to be 10ftx15ft. (or any combination that adds up to 150sf)
I repeat this for each consumer:
2 Cows use the barn. It needs to be 1500sf to produce 14,000 Gal.
8 Humans use the home. It needs to be 1500 sf to produce 14,000 Gal
3 Pigs use the pig shed. It needs to be 170sf to produce 1,500 Gal
10 Chickens use the coop. It needs to be 150sf to produce 1,400 Gal.
Greenhouse waters its own plants 100sf produces 935 Gal.
For rough estimates in New Mexico, I can multiply 9 times the sq ft to calculate approximate water collection.
100 sf = 900 Gal
1500 sf = 13,500 Gal
170 sf = 1,530 Gal
Which means I can divide the water by 9 to get the sq ft needed. (both of these only work in New Mexico because 15 inches of rain X 0.623 =9.345. In your area, with your annual rainfall you’ll have to find your own shorthand.
Next is the Extra Water. I don’t want to plan to use every drop of water every year or else in a year of drought, I’m in trouble. So I also collect water off my guest house and my garage to filter and store in times of need. These add to the overall house water and is stored in cisterns underground so that I can use it wherever it’s needed via hoses when one of the other sources goes dry.
I want to make sure that every year, I have more water in reserve than I did the previous year. In the end, this is how I become self reliant.
I went into depth covering how to calculate your water need and plan for its rainwater collection. Next I’ll show you how to conserve the water you have, and how to reuse water to make it go even further.
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