There is a great deal of emphasis placed on conserving water these days and there is a very easy and efficient method to help you do just that. By capturing rainwater which falls on the roof of your home or other structure you can save this water for later use. (This is also known as rainwater harvesting.) A large variety of rain barrels and collection systems are available. The size and type of barrel or container you want is limited only by how much you want to spend. The average rain barrel will hold approximately 50 to 55 gallons of water.
How Much Water Runs Off Your Roof
The key to conserving the rain water is to capture it as it runs off your roof. Generally this is a very simple task of installing a diverter on one of the gutter downspouts. This diverter routes the water to a rain barrel for later use in watering your garden. Even a modest sized rain barrel will be filled to capacity with only moderate rainfall.
According to Rain barrel guide, for every one inch of rainfall, 600 gallons will land on every 1,000 square feet. If your home has a 2,000 square foot roof area, and you capture all runoff water, you would collect 1,200 gallons during a one inch rainfall. This is in a perfect situation. In most cases some water is lost due to evaporation, missing the gutter, wind, or other effects. As a general rule you should expect to collect seventy to ninety percent of the total rainfall.
With a one half inch rainfall on a rooftop of 2,000 square feet, you should expect to collect 420 to 540 gallons of water. (300 gallons per 1,000 square feet, at 70%- 90% collection rate) This rainfall would fill ten average size rain barrels, far more than the average homeowner will install.
How to Use Collected Rainwater
While the rain water you collect should not be considered potable (safe to drink) it can certainly be used to water shrubs, flowerbeds, or gardens. If your rain barrel is above ground, the water will flow out under the force of gravity. This will not allow you to use a standard sprinkler, but you can use soaker hoses or a standard garden hose.
For a more automated system you can install a timer on the outlet of the rain barrel set to deliver water for a set period of time each day. These timers are battery operated and very simple to set and use. It will also help insure your plants/garden are watered on a regular basis, at least until your water supply is depleted.
Types of Rain Barrels
Composters.com shows dozens of different rain barrels. Some are very plain while others are decorative and very attractive. Most range in size from 40 to 70 gallons, but some have a capacity of as much as 300 gallons. Of course, the larger the barrel/tank size the more room it will occupy. For the smaller rain barrels you may only need to divert a single downspout. For a much larger tank you may need to divert multiple downspouts in order to be certain to fill the container.
For a much larger collection system you can have a septic tank installed and direct all harvested rainwater into the tank which can be up to a 2,000 gallon capacity. This will be more expensive and will require a pump to remove the water, but it does allow for a very large collection capacity, and the entire system is concealed. Base your collection and storage system on your needs, as well as the rainfall tendencies in your area.
Sources
- Rain Barrel Guide - How Much Water Can You Collect In Rain Barrels During A Rainfall
- Composters.com - Rain Barrels
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