You can make a rain barrel for about $20. Alternatively, you can install a complex network of pumps and tanks that can cost thousands of dollars. Most homeowners don’t need the latter. Rainwater accumulates faster than you think. You don’t have to make a big investment to start saving money on your water bill.
The calculation is surprisingly simple.
Consider a standard 1,000 square foot roof. you capture about 600 gallons of water. That is over 2,200 liters. Your roof acts as the catchment area. The gutters direct the runoff water to the collection container.
But your roof might be bigger or smaller. How do you calculate your specific potential yield?
Calculate the water potential of the roof
You need to measure the floor area of your home, including overhangs. Use the outside length and width.
Multiply these two numbers together.
For example, consider a 30-foot by 40-foot house. This provides a catchment area of 1200 square feet. Next, use the conversion factor. One inch of rainwater per square foot produces about 0.6 gallons.
1200 times 0.6 equals 720 gallons.
This means that 1 inch of rainwater on a 30×40 home can produce 720 gallons of rainwater. Its volume exceeds 2700 liters. There is a large amount of free water in the tank.
Look at your water bill. The difference between summer and winter is often very large. Why? Because outdoor usage drives up the cost. The average American household uses 30 percent of its total water consumption for gardening and landscaping. Capturing rainwater targets that specific waste.
DIY rainwater collection safety precautions
Water is convenient to store. It can be dangerous if you are not careful.
Remember to cover the rainwater tank. An open tank invites mosquitoes. It collects leaves and debris. But most importantly, it poses a danger to children and pets.
Children can drown in 2 inches of water.
An uncovered barrel is a trap. Close the lid tightly. If possible, keep it out of reach.
Installing a bucket requires more than just stacking plastic containers under the downspout. You need to consider placement, overflow management, and filtration. But first, you need to know if the yield on the roof is right for your needs.
The numbers above show your raw potential. The next step is to turn this potential into a working system without going beyond the basics or creating a breeding ground for mistakes.
