Rain Water Harvesting

Question: We have had an abundance of rain this spring but I know I will wish I had stored some of it for the hotter and drier weather that is soon to come. Is it difficult and costly to install a cistern system to store water?

Answer: Cisterns have been used for centuries and the technology is well developed. We in the Southeast have not taken advantage of these systems as much as our neighbors to the west for many reasons. Cheap and plentiful water not to mention our fairly high average rainfall are the main reasons. Water is still pretty cheap considering it is necessary to sustain life but the cost has gone up dramatically over the past several years. A large percentage of potable water is used for landscape purposes and this must come to an end if we continue to increase in population in the Southeast. Cisterns offer a great opportunity to capture rain water during the rainy periods for later use in the landscape or possibly to even wash clothes or flush commodes.

Cisterns can vary tremendously in cost depending on size and desired appearance. If you want to try rain water harvesting on the cheap I would suggest you start with a simple rain barrel attached to your gutter downspout. A 55 gallon drum barrel can be attached in a couple hours with a few simple tools at a cost of fifty to a hundred dollars depending on how much of a “do it yourselfer” you are.

A rain barrel will not provide enough water to maintain a thirsty lawn or a large garden but would provide an inexpensive drink for a container garden or a small vegetable or flower garden. If the barrel is above the area to be watered or you are just filling up a watering can you will only need the help of gravity to water your plants. However, a small submersible pump can be dropped into the tank to pump the needed water out through a water hose to any part of the landscape.

Larger cisterns can be much more expensive but can be designed to provide all of your irrigation needs and some of your non potable water needs in the home. These systems may consist of large plastic, concrete or metal tanks that can be either above or below ground. You can even purchase large water bags that are flat when empty and expand as they fill. These bags can be stored under a porch in a basement or even in the crawl space of a home.

If you plan to irrigate a large area and you want enough water stored to do the job you will need to do some math. North Carolina State University has a great web site with lots of rain water harvesting information to help design a large system and to calculate the estimated time it will take to recoup your investment.

On a smaller scale the Alabama Cooperative Extension System will conduct a Rain Water Harvesting workshop at the Birmingham Botanical Gardens on July 14th , from 1:00 – 3:00 PM. This workshop will cover the basics of rain water harvesting and demonstrate the conversion of a 55 gallon drum into a ready to use rain barrel.