An important component in any drip irrigation system are the manual or automatic valves, with automatic drip irrigation requiring the use of electric valves.

When planning a drip irrigation system, the landscaping is key – different types of landscape, even within the same garden plot, require different types of irrigation. So an automatic drip irrigation system must be designed in zones, with a separate valve opening (or closing) the irrigation in each distinct area.

The process starts at your home's outdoor faucet, or "hose bib." A plumbing piece called a "hose bib manifold" is screwed onto the faucet, effectively turning your one-hose faucet into four faucets. Another plumbing piece called a "pressure reducer" is screwed on each of the four faucets – the water pressure in an average American home can run as high as 100 pounds per square inch, far more than a drip irrigation system needs.

Automatic electric valves are screwed onto each of the Drip Irrigation Electric Valves pressure reducers. These valves will open or close in answer to commands from the drip irrigation system's timer (sometimes called a controller). The electric valves run on very low voltage, and the weather-proof automatic timer is battery operated.

The timer can then be programmed to tell each valve when to water it's assigned zone, and for how long. Once opened, each valve sends water down a length of half-inch polyethylene tubing to the area to be watered, then quarter-inch tubing takes water from the main line to the base of the plants.

Drip irrigation systems can utilize manual valves, as well – but drip irrigation using electric valves means there's one less task for the busy gardener to worry about.