Irrigation Equipment

If you are considering operating and maintaining an irrigation system yourself, it is highly advisable to become familiar with the various parts of an irrigation system. 

Water Meter

The water meter is generally located near the street and measures all water used at the residence.  You can find out how much water an irrigation system uses and if the irrigation system has a leak by reading the water meter.

Water meter

Irrigation Main Line

The pipe that comes from the water meter to the house is the main water line. An irrigation main line is a pipe that branches from the house main line in order to supply water throughout the irrigation system. This part of the system is under constant pressure.  A manual valve must be inserted where the irrigation main line connects to the domestic main water line.  This allows for the irrigation system to be turned off while making repairs to the system without an interruption of water to the house.

Manual Valve

A device, operated by hand, to control the flow of water through a pipe.  Commonly used to isolate and stop the flow of water to one or more sections of an irrigation system while installation, maintenance, or repairs are being performed. 

Electric Valve

An electric valve automatically opens when it receives an electric current through wires connected to the timer.  The valve closes when the current is off.  Electric valves break the flow of water from the pressurized pipe (irrigation main line) to the non-pressurized pipes (lateral lines) of an irrigation system.  Each valve allows water into an irrigation line when opened.  Electric valves require 24volt ac. 

Automatic irrigation valves.

Backflow Preventer

This is a valve that stops water from flowing ‘backwards’ from the irrigation system and back into the house, or domestic, water supply line. For obvious health reasons, irrigation systems require some sort of backflow device.  Anti-siphon valves are the simplest form of backflow prevention.  To function properly, anti-siphon valves must be installed 12” above the highest emission devices (sprinkler, drip emitter, etc.) on each valve.  A special type of backflow prevention device is required by code if the 12” installation cannot be met. Check with your local building department for any additional, local requirements.

Filter

A filter prevents debris from entering an irrigation system.  Always use filters on low volume systems. Most of the time filters are purchased separately, however, some manufacturers have valve, pressure regulator, and filter as one unit.

Pressure Regulator

A pressure regulator is a valve that provides a set, or adjustable, water pressure to a system or line. Emission devices (sprinklers, drip emitters) operate best at different levels of water pressure. A pressure regulator on the entire system, or individual pressure reducing valves, may be needed to keep emission devices within an optimal operating range.  

Irrigation controller.

Controller (Timer, Clock)

A controller is a device that is programmed to send electrical currents to automatic valves in order to turn them on at a pre-set time, for a specific length of time. They are usually mounted on an inside wall of the garage.  A controller that has a capacity for multiple programs is recommended. With multiple programs, irrigation valves can be individually scheduled (programmed) to meet the needs of specific water-use plant types.

Controller Terminology:

Multiple Independent Programs

An irrigation program allows for the setting of specific watering days. Having more than one program allows various valves to be set for different days. Ideally, a program will be capable of weekly (7 day) and interval programming.  Weekly programming involves setting the watering days on certain named days of the week, such as every Monday, Wednesday, and/or Friday. Weekly programming is primarily used for lawn irrigation.

Interval programming is a set number of days between irrigations. This type of programming is best for all non-turf areas as it is not necessary to have a specific day left unscheduled due to the mowing of lawn.  A controller that allows intervals of up to once every 30 days is preferable.     

Multiple Start Times

Multiple start times allow the system to water more than once a day. For example, a controller with multiple start times can water the lawn for 5 minutes, turn off for 60 minutes, and turn on again to water an additional 5 minutes. Cycle watering allows the first irrigation water to soak into the soil (with little to no run off) before applying the second application. Clay or loamy soil, and sites with slopes, need multiple cycles.

Variable Run Times

Allows for run times to be set for as little as 1 minute to 200 minutes, in a single cycle. Cycle times can be precise rather than approximate with variable run times.

Water Budgeting

A water budget feature allows you to easily adjust the watering run time on each irrigation valve, program, or entire controller, by a percentage based on the weather.  Use this feature to make daily, or weekly, adjustments for weather conditions above or below normal for the time of year.  

Non-volatile Memory

Non-volatile memory retains the set program in the event of a power failure.

Battery back-up

Battery back-up will retain the set program and internal clock in the timer in the event of a power failure. 

Rain Shut-off Device Capability

This feature allows for installation of a device to automatically override the controller settings and turn a clock off during a rain.

Rain sensor

Consider purchasing a ‘Smart’ or ET (evapotranspiration) controller. ‘Smart’ sprinkler timers automatically adjust the different irrigation schedules in a timer throughout the year. Call your water provider for a list of ‘Smart’ sprinkler timers.