Water Conservation

  • Difficulty Rating: Beginner

Rainwater harvesting is not new. It has been used around the world for thousands of years.

Today, we hear the term more and more, but not in terms of providing potable water for drinking, but as a way to provide an irrigation source for landscaping. For instance a roof area of only 1,000 square feet can provide approximately 600 gallons of water during a one inch rainfall.

Containment systems like rain barrels are becoming popular again as water quantity becomes scarcer and quality becomes more questionable. Areas known for low rainfall amounts have been using these systems for decades.

The most basic form of rainwater harvesting is simply collecting the water and distributing it immediately to the plants. It's no surprise this method is referred to as a "simple" system. Rainwater harvesting using a rain barrels or other collection devices are classified as a "complex" system but don't let the name deter you. Complex systems simply refer to storing the water after it is collected and providing a way to distribute the water later.


The term catchment is any area from where the water is harvested. The amount of water harvested from a catchment depends on its size, surface texture, slope and rainfall received. If your roof is 2,000 square feet, and your area averages 20 inches of rain per year, you can harvest 24,000 gallons of water from your roof each year if you have a container large enough to store it.



Runoff is the water that flows off the surface and that could be harvested. This is the water we are able to capture and use immediately or at a later date to irrigate our plants and landscapes.

The conveyance system or diverter system channels the water from the catchment to the storage tank. For example, the holding area is the rain barrel and the diverter system would be attached to the downspouts to collect the water from the catchment. Well designed systems offer a diverter system that prevents the overflow of the rain barrel when it is full and diverting excess water into the downspout – ensuring that it moves away from your home and foundation.

Above-ground water collection systems have the advantage of usually being less expensive to install and maintain, but they are much more obvious. Be sure to check your local zoning and neighborhood guidelines before installation.


When it comes to maintaining your rain collection system, no matter where it's located, there are certain initial and ongoing steps that should be conducted to keep your system operating properly.

  • Make sure to that the collection system has a cover that adequately encloses the unit first for safety and to minimize intrusion by animals or breeding of mosquitoes.
  • Maintain a debris-free conveyance system. This would include inspecting gutters and downspouts. Regular cleanings will prevent blockage.
  • Periodically flush debris from container bottom.
  • Inspect your system after a heavy rain and at the end of the rainy season to if any obvious concerns need to be addressed – look for leaks, overflows, or water in inappropriate areas.
  • Look for any occurrences of overflow and determine a plan for addressing the harvesting of this excess water if appropriate – perhaps add an additional collection system or overflow container.

Good for Plants


Rainwater is always a good source for plants. It's free of salts and other minerals that can harm plants and root growth. The harvesting of rainwater can be used in a large-scale environment, such as schools, parks, office parks, etc. But in the home landscape, it's a relatively easy and inexpensive system to set up and maintain.

Good for the Wallet

After the initial cost of installation (if any), all the water collected and used is free. Not only will you be realizing the savings in real dollars, but more importantly, you'll be conserving and protecting a valuable resource as well.

The wise use of water for garden and lawn watering not only helps protect the environment, but saves money. In addition, calculated and efficient use of water provides optimum growing conditions. There are several simple ways of reducing the amount of water; including growing low water use species (xeriphytic species - plants that are adapted to dry conditions), mulching, adding water retaining organic matter to the soil, and installing windbreaks and fences to slow winds and reduce water evaporation. In addition, water drip water techniques offer an efficient use of available water. Watering in the early morning before the sun is intense helps reduce the water lost from evaporation. Installing rain gutters and collecting water from downspouts also helps reduce water use.

Choosing Plants for Low Water Use

Several different plant species exist that require low moisture and reduced water content. Cacti, succulents, and small and narrow leafed evergreens are always excellent choices, however many routine plants from across the United States have adapted to low levels of moisture. Develop garden layouts that use known low moisture plants, and work closely with your local State extension service to select other plants that have adapted to low water levels. Selecting and using plants with lower water usage can provide a beautiful garden and reduce overall water need.

Efficient Watering Methods

There are several methods that will provide efficient and effective water to plants and vegetables; Trickle or drip irrigation systems help reduce water use, but at the same time meet the needs of plants. These methods use very small amounts of water to supply the base and roots of the plants with water – routinely watering with a small amount. Because the water is applied directly to the soil, rather to the top of the plant, water evaporation is reduced. Many gallons of water are needlessly wasted when sprayed over an entire garden.

Watch a video about water conservation with Joe Lamp'l, Master Gardener.