Garden Watering Systems: An Overview

A garden watering system begins at an outdoor faucet or a dedicated pipe branching from the main water supply. The water is regulated by a controller and passes through a network of pipes to an array of devices that spray water into the air or drip it onto the ground. The requirements of your garden and landscape are the main parameters to consider when designing a system, and modern technology provides a host of options for those for whom water conservation is a priority.

If you're planning a new watering system, you'll be faced with a choice between a conventional sprinkler system and a drip system. The arguments for drip technology are powerful, but it isn't the answer for every situation.

Drip emitters deliver water where you want it and are 90 percent efficient. Sprinklers, on the other hand, deliver water with 50 percent to 70 percent efficiency. 

Unlike the pipes for a sprinkler system, which must be buried, drip irrigation pipes sit above ground, and you can modify them at will. That may not be an advantage when it comes to watering the lawn, but in a garden, the flexibility to curtail water flow at one location while increasing it at another is a boon that allows you to keep up with the changing needs of growing plants.

Drip systems can be augmented with micro sprinklers to water larger areas and ground cover. While not as efficient as drip emitters, micro sprinklers are far more efficient than conventional sprinklers.

Sprinklers are more reliable than drip emitters. They seldom clog and last for years. 

Sprinkler pipes are underground, out of the way and require little maintenance.

You can select from a range of sprinkler types, from bubblers for watering individual plants to impact rotors capable of throwing water in a 50-foot radius. In between are fixed sprayers, gear-driven rotors and multistream rotors, and all disappear safely below the ground when not in use.

Unless you plan to turn the water on and off manually every day, your watering system needs a controller. Most watering systems are divided into zones, each with its own magnetic valve, and the controller sends a signal to each valve to open and and close it. Many controllers have an internal timer that the user can program, but clock-timer controllers waste water, since they often open the sprinklers when it's raining or the ground is already moist. The U.S. Environmental Protection Agency estimates that such inefficiencies lead to a net waste of billions of gallons of water annually.

To address this waste, the EPA began certifying WaterSense controllers, which it estimates could save 120 billion of gallons of water every year if every home-watering system used one. A controller with the WaterSense label monitors local weather conditions through an Internet connection and adjusts the watering schedule accordingly. It can also sense humidity in the air and -- if the garden is equipped with a sensor -- the moisture of the soil.

Besides a controller and a delivery system for the water, a garden watering system needs other components:

One or more check or anti-siphon valves to prevent water from flowing from the garden back into the drinking water. These are mandated by most local health authorities to prevent contamination of the drinking water.

Filters to prevent sediment from the water supply from clogging drip emitters and sprinklers.

Pressure regulators to maintain the water pressure at a safe level.