Irrigation System Installation
Proper installation of the irrigation system is required for efficient
irrigation and water conservation. The following are general guidelines for
irrigation system installation.
- Call utility companies (telephone, cable TV, electric, gas, and water) for
blue stake service to mark all utilities in the construction area before
digging or trenching.
- Use drawings and specifications to mark locations of valve boxes, pipe,
sprinklers and drip emitters before installation. Mark locations with flags or
stakes. This visual inspection of the system allows for minor adjustment in the
system layout before installation.
- If the irrigation system is being installed in phases, plan ahead so the
landscape does not need to be disturbed for installation of pipe and wire
- Installed pipe should be deep enough so that ground frost, soil aeration
and tillage operations cant disturb the pipe. For medium to large
irrigation projects, a mechanical trenching machine may be rented to reduce
labor. The pipe and wire should be bedded in soil without large rocks. Most
pipe used in irrigation systems is PVC which requires both threaded and glued
connections. Two layers of teflon tape should be used on the male end of PVC
threaded connections. Excess teflon tape and over tightening threaded
connections can cause excessive stress on joints. One turn past hand tight in
general is sufficient. Flush the pipe line before installing sprinklers.
- Wire conections must be make between each valve solenoid and the irrigation
controller (time clock). Wire splices must be waterproofed. Wire nuts and
plastic tape are not waterproofing. Waterproof wire connection kits can be
purchased. Make all wire splices in valve boxes.
- Use white wire as the common and colored wires for hot wires.
Valves should be installed in valve boxes which allow access to the valves for
repair or replacement.
- Rotating and spray sprinklers should be attached with appropriated size
swing or flexible connections (figure 6). These types of connections provide
protection to the pipe line and allow adjusting the height and level of the
sprinkler. Install part circle sprinklers so that they are irrigating the
proper area. Adjustment of operating sprinklers should be made immediately
after installation of irrigation system.
- Trenches should be back-filled and watered, then back-filled again. This
reduces settlement of soil in the trench below the grade of the landscape.
- During and after installation, drawings should be made with the true
location of all irrigation lines (as-built plans) to assist in
trouble-shooting, maintenance, repair and future modifications.
- Drip irrigation systems are sometimes installed on the surface of the
ground. When installing drip emitters in the tubing remember that the
irrigation tubing is longer on a hot afternoon than in the cool mornings During
installation of irrigation tubing allow enough slack in the tubing to account
for temperature induced tubing length differences.