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Rainwater Harvesting

Water is life. Three days without it, and we’re knocking on heaven’s gates. Because it is one of the three basic requirements for staying alive, who wouldn’t like the idea of free water? It is a natural resource and should be free, right?

If you have a well or live next to a spring, you already enjoy the privilege of fresh, clean water without having to purchase it as a commodity. If not, water is a necessary monthly expense paid along with the other bills.

Collecting rainwater is a practical and inexpensive way to secure an additional source of fresh water, and it is free. Having our own water source provides security to our family by increasing our level of self-reliance. It serves well as an emergency backup water supply in the event restrictions are placed on municipal water usage.

Other benefits of rainwater harvesting include controlling runoff, curing drainage problems and preventing erosion. Harvesting rainwater has been a “thing” since the birth of man, it’s certainly nothing new. However, as awareness increases over environmental concerns and challenges, water conservation is gaining popularity more than ever. For those dwelling in urban communities where the only water source is at the sink or grocery, having the ability to access another supply is crucial.

Creating a simple rainwater harvesting system is as easy as setting a trash can under the eave of our house. Of course, we can do better than that, and expand our capabilities with a few more dollars and a little ingenuity.

The basic components of an effective rainwater system include the following:

1.) Catchment. This is primarily a roof, but there are stand alone options like those shown in the photos below. Some of these may be purchased as a complete system, or you can build your own with a few common materials you find at a local box store like Home Depot, Lowes or Walmart.

2.) Conveyance. This is the method of controlling and directing the flow of rainwater from the catchment system to your storage container, and consists of gutters, pipes, ditches, tarps, etc.

3.) Strainers, Screens, Filters. It’s important to eliminate debris from your collected water. You can do this with a mesh wire cloth, screen and filters. The mesh will stop larger debris such as leaves and twigs, the screen is a secondary medium to prevent smaller particles and filters can take out the unseen contaminates.

4.) Storage. The four basic materials used in storing water are plastic, metal, concrete and wood. Something as simple as a plastic or metal trash can will get you started, but for about the same price, you can re-purpose plastic 55 gallon barrels that will do a better job with more capacity. IBC totes are another popular method of storing water and are available in 275 and 330 gallon capacity. To prevent the growth of algae and bacteria, the container you choose should be opaque to prevent sunlight from reaching the water. A simple way to achieve this is with a cover or paint. Any container you use should also be of “food-grade” quality. In other words, if it has been used in a prior application, make sure its contents were safe for human consumption.

5.) Treatment. Any water intended for drinking will need to be purified. Boiling is probably the best way to purify water, but that only works with small quantities. Collected rainwater is typically purified with filtration, disinfection ozonation and absorption. Filtration for drinking will require a high quality filter that removes bacteria, chemicals, etc., and renders the water safe for consumption. Disinfection can be accomplished with chemicals such as chlorine or water purification tablets. Both of these will alter the taste of your water. Ozonation requires special equipment to infuse the water with ozone gas and absorption uses activated charcoal to bind with undesirable substances in the water.

6.) Distribution. This means how you will transfer water from the storage container to its final destination. If you are using the water to irrigate your garden, you may use a water hose or a watering can. If the water will supply your home as a whole house system like the examples below, it would consist of a pump and plumbing to route water to the desired locations inside the home.

Wet and Dry Systems. A good example of a wet system for rainwater harvesting is in the photo on the left below. It consists of the storage tank’s location being removed from the catchment area, and connected with a longer pipe usually buried underground. Because of the design of a wet system, water remains in the lower lying sections of the connecting pipe.

The photo on the right below shows a dry system. The tank is set closer to the catchment area so the rain runs directly into the tank. When it stops raining, the connecting pipe is dry.

More natural ways to collect and conserve rainwater can be accomplished with permaculture techniques such as swales and water gardens. Swales are simply trenches dug across a slope to slow down and retain runoff. They can also be arranged in a landscaped garden design to route and pond water in smaller areas. Swales help control erosion and they allow water to slowly seep into the soil.

The following images show how to determine the amount of rainfall you can collect from your roof.

Here are some examples of how to use the formula. If you don’t know the square footage of your roof, using the square footage of the floor in the area where you will be collecting the rainwater will work and get you really close to the actual amount.

I hope this article was helpful, and you will begin some form of harvesting the benefits of harvesting rainwater. Cheers!

  • Note: The photos in this post were taken from Google images. If you are the original photographer, please contact me for credit or to promptly remove the photo from the article.
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