CIT key terms

The pressure of water when it is not moving, measured in psi. It shows the supply pressure available before any flow begins and is used to decide whether the system needs a pressure regulator.

The pressure actually remaining at a point while water is flowing. It is always lower than static pressure because of friction and elevation changes, and it determines how well heads and emitters perform.

The drop in water pressure caused by water rubbing against pipe walls, fittings, and valves as it moves through a system. It grows with higher flow, smaller pipe, and longer runs.

The volume of water moving through a pipe or device in a given time, usually expressed in gallons per minute. Designers match flow rate to pipe size, valve capacity, and the number of heads per zone.

A banging or pressure surge that happens when water flow stops abruptly, such as when a valve slams shut. It can crack fittings and pipe, so slow-closing valves are often used to reduce it.

The depth of water a zone applies per hour, usually stated in inches per hour. It lets you compare zones with different head types and set runtimes that avoid runoff.

A measure of how evenly a zone applies water across the irrigated area. Low uniformity means some spots get too much and others too little, so runtime must suit the driest areas.

A group of plants with similar water needs, sun exposure, and soil that are irrigated together on one zone. Grouping this way lets each area receive an appropriate schedule.

A design practice of using heads or nozzles that apply water at the same rate within a zone, so no area is over- or under-watered. Mismatched rates create soggy and dry spots.

Any actual or potential link between the drinking water supply and a source of contamination, such as a hose left in a bucket of fertilizer. It is the condition that backflow turns into a health hazard.

The unwanted reverse flow of water in a piping system, caused by backpressure or backsiphonage. Backflow can carry pollutants or contaminants into the potable supply and must be prevented.

A device or assembly installed to stop reverse flow from reaching the potable water supply. Selection depends on the degree of hazard, and many types require annual testing by a certified tester.

A testable backflow assembly with two check valves and a relief valve that discharges if pressure reverses. It protects against high-hazard connections and must be tested on a regular schedule.

A physical separation between the end of a water supply pipe and the flood-level rim of a receiving vessel. It is the most reliable form of backflow protection because it has no moving parts.

A testable backflow device that uses a check valve and an air inlet to stop backsiphonage. It must be installed above the highest downstream outlet and cannot be used where backpressure can occur.

The control device that turns zone valves on and off according to a schedule. It stores programs with start times, runtimes, and watering days, and sends low-voltage signals to the valves.

An electromagnetic coil mounted on a valve that opens or closes it when the controller applies voltage. Its resistance can be measured to diagnose wiring and valve problems.

The loss of voltage along a wire run caused by resistance in the conductor. Long runs or undersized wire reduce voltage at the valve, which can keep solenoids from opening reliably.

The size of an electrical conductor, commonly given in AWG numbers where lower numbers mean thicker wire. Gauge is chosen from valve load and distance so voltage drop stays acceptable.

A device that interrupts the controller's schedule when measurable rainfall occurs and lets watering resume afterward. It saves water and prevents runoff from overwatering during storms.

A remote-control valve that opens water flow to one zone when energized by the controller. Globe and angle styles use a solenoid and diaphragm to start and stop flow.

A valve at the point where the mainline leaves the water source that opens only while a zone is running. It limits water loss if a lateral breaks and may be electric or hydraulic.

A sprinkler head that rises from the ground under water pressure and sprays a fixed pattern, then retracts when the zone shuts off. It suits small turf and planting areas.

A rotating sprinkler head that sweeps one or more streams back and forth over an area, covering long distances at a low application rate. Rotors are typical for large turf and need matched nozzles.

The interchangeable opening on a sprinkler head that shapes and meters the water stream. Nozzle size and pattern determine flow, throw distance, and precipitation rate.

A device that reduces incoming pressure to a stable, lower level for the heads or emitters downstream. It protects components from damage and keeps spray patterns and flow rates accurate.

A small device that releases water slowly at a rated flow, such as one or two gallons per hour. Emitters deliver water to the root zone with little evaporation or runoff.

The pipe downstream of the zone valve that carries water to the sprinklers or emitters in a zone. Laterals are usually smaller and buried shallower than the mainline.

A plastic or concrete box set in the ground over valves, giving access for service and shielding the valve from soil and moisture. It should sit flush with grade and drain properly.

The depth of soil measured from finished grade to the top of a buried pipe. It must meet local code and be enough to protect pipe from traffic loads, freezing, and future digging.

The process of having buried utilities marked before digging so the crew does not strike gas, electric, or communication lines. Most areas require it by law before excavation.

Running water through new or repaired pipe to clear dirt, debris, and cuttings before heads or emitters are connected. Flushing prevents clogged nozzles and damaged valves.

Draining or blowing compressed air through a system to remove water before freezing weather. Trapped water expands as it freezes and can burst pipe, valves, and backflow assemblies.

A test instrument that measures voltage, resistance, and sometimes current. Technicians use it to check controller output, solenoid resistance, and continuity when troubleshooting electrical faults.

The combined water loss from soil evaporation and plant transpiration. Scheduling based on this value replaces the water a landscape actually uses instead of running a fixed clock schedule.

A controller that adjusts runtimes automatically using weather data, evapotranspiration, or soil moisture information. It reduces overwatering while still meeting plant needs when programmed with correct site data.

A scheduling method that splits a long runtime into shorter cycles with soak periods between them. It lets water soak into the soil instead of running off slopes or tight clay.

A safety procedure for shutting off and locking an energy source, such as a pump circuit, before service work. It prevents accidental startup or release of stored energy while someone is working.

A protective system such as sloping, shoring, or shielding used to keep trench walls from collapsing. Trenches about five feet deep or more require protection under workplace safety rules.