As stormwater runs off of impervious surfaces like rooftops, driveways and sidewalks pollutants such as pet waste, dirt, grass and leaves, fertilizer, pesticides and oil from cars enters our storm drain system and ultimately discharges to our local waterways. These pollutants can adversely affect the local water quality increasing costs for water treatment and negatively impacting the local ecosystem.
A rain barrel or larger cistern system that collects and stores rainwater from your roof that would otherwise be lost to runoff and diverted to storm drains and local waterways. A rain barrel is relatively simple and inexpensive to construct and can sit conveniently under any downspout.
Water collected and stored in a rain barrel or larger cistern is free water that you can use for your lawns, flowers, vehicle washing or outdoor home cleaning. This system reduces stormwater runoff, conserves water usage and protects our natural resources. Remember water collected in these systems are not to be used for drinking, cooking or bathing!
So how does a rain barrel or cistern work? The following basic components are involved in every rainwater collection system:
- Catchment Area - The roof is the most common and adaptable area to use for rainwater collection but any area where rain water runs off and can be directed to a storage area such as a drainage swale, driveway or sidewalk can be the focus for collecting rain water.
- Conveyance System - Once you identify the catchment area you need to have a way to transport the rain water to the storage tank. In most cases this will be a gutter system but a PVC pipe, rubber hose or tubing can be used as well.
- Storage Tank - Storage tanks can be elaborate concrete structures or simple plastic containers like garbage cans or barrels. These tanks are placed above the ground in order to take advantage of gravity. Below ground tanks require a pump and will increase the cost and maintenance time.
- Filtration - As water sheds off a roof or other catchment area, it may pick up leaf debris, bird droppings or chemical agents from the roof material. These are not harmful to plants but a simple screen mesh to keep out leaf debris and insects will prevent the system from clogging and insects from breeding. I will still be a good idea to clean the tank periodically to avoid debris build up.
- Water Distribution - This will be limited to a watering can, soaker hose or garden hose due to the low water pressure. This system is using gravity so the height and water level of the storage tank will determine the water pressure and ultimately the distribution method. However installing a pump is an option which can increase your distribution options.
There are many different designs and types of rain barrels and cisterns. Do your own homework by visiting the following websites, go to your local library or sign up for a rain barrel class!
Visit the Texas Agrilife Dallas Extension website to sign up for a rain barrel class! Rainwaterharvesting.tamu.edu