Rain barrels and rainwater collection systems are making a stylish and functional comeback in America. With the uncertainty of climate change and continuing drought problems plaguing many parts of the country, capturing and using rain is a practical way to conserve resources.

Collected rainwater can be used for watering gardens and even for non-potable applications such as flushing toilets. Whether it is to offset high water bills in the summer, keep the garden green during drought cycles, or simply lessen the burden on storm drain systems, catching and using rain around the home makes sense.

Most homeowners use treated municipal water for drinking, dishwashing, cooking, bathing, and watering yards. In fact, it is estimated that from 8% to10% of the water used annually by Americans is poured onto gardens and lawns. But treated water is increasingly scarce and expensive, and it’s not even the best for plants—especially native plants—because it may contain fluoride, chlorine, and certain impurities. Rain provides the best, purest water for your landscape.

Assembling a rainwater harvesting and storage system can be as easy as setting up a rain barrel or investing thousands of dollars in an intricate rainwater retrieval, filtration, and storage system. Regardless of the size and complexity of the system you want, understanding the basics can make your decision much easier. And, if you intend to do some or all of the assembly, this knowledge can help you design a manageable project.

The amount of rain you can collect in a rainwater collection system is determined primarily by the rainfall in your region and the size of your roof. The accepted rule of measurement is to determine the cubic feet of water that will fall on your collection surface and then convert the cubic feet to gallons by dividing the monthly average of rainfall by 12.

Once you have that number, simply multiply it by the square feet (width x length) of the roof. The equation looks like this:

Inches of rain ÷ 12 x square feet of collection space = gallons of water

So, by measuring the size of the collection area (that part of your roof that will drain into your storage container) and finding out the local monthly average rainfall, you will be able to figure out how fast your storage containers will fill up.

For example, Los Angeles receives, on average, .72 inches of rain in the month of April. With a 60-by-30-foot collection surface (1,800 square feet), a Los Angeles homeowner can expect to collect about 108 gallons in April. However, during the month of July, when rainfall averages only .01 inches, the same system will collect less than 1 gallon of water. Having a storage system that can hold several hundred gallons of water can help that homeowner make it through the dry season without having to use municipal water.

Equipment for Rain Water Collection

A full rainwater harvesting system consists of several parts that together capture, move, and store the water. Perhaps the most important of these is the collection system.

Fortunately, homes already have a rainwater retrieval system in place—the roof, gutters, and downspouts. Equally fortunate is the fact that tying into this system is easy and affordable, which is why most rainwater harvesting systems are designed to capture water that falls on roofs. Of course, rainwater can be harvested from other areas, too, such as driveways, open-air patios, and other non-permeable surfaces.

Storage containers are really where spending the money matters in a rainwater harvesting system. The more water you want to store, the more expensive the system will be. In arid areas where rainfall is light and drought is common, large storage systems that may include underground storage tanks or large cisterns can be expensive but well worth the money.

If water falls often in your region, you might consider a smaller system to handle your watering needs during the occasional dry spell.

Aesthetics play an important part of selection, as well. If you are seeking the classic look, you can readily find used whiskey barrels online.

Make sure that rainwater collection devices are covered and tightly sealed. This helps minimize mosquito populations and prevent them from becoming a drowning hazard to small children. Also, tightly lash or stake your storage device to the ground so that it won’t easily fall over. One gallon of water weighs over 8 pounds, so even a half-full 55-gallon drum can be a crushing hazard.

If you want your system to last, it must be drainable for winterization. Water expands when it freezes—one cold winter can spell the end to your whiskey barrel. Likewise be wary of a storage device that doesn’t allow you to easily clean it. Even with mesh screens and filters, chances are good that dirt and debris will eventually make their way into your container. Being able to completely empty the storage unit will allow for easier cleaning.

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About Don Vandervort
An avid builder and remodeler, Don Vandervort has developed his expertise for more than 30 years, as Building Editor for Sunset Books, Senior Editor at Home Magazine, author of more than 30 home improvement books, and writer of countless magazine articles. He appeared for 3 seasons on HGTV’s “The Fix,” and served as MSN’s home expert for several years. Don founded HomeTips in 1996. Read more about Don Vandervort