The various components of the irrigation system are tested as they are installed and the performance of the entire system is tested once the installation is complete.

As the pipes are laid and flushed, joints are inspected for leaks. Once the pipes are partially backfilled with the joints exposed, the system is brought up to working pressure.

The blocks that are grouped in operations are opened. Pressure readings are taken in front of and after the valves. These are compared with the values noted on the irrigation design plan in the Pressure and Flow at Nodes table. If the readings are not correct, it may be an indication of wrong pipe size, incorrect hydraulic valve settings, or pump or filter malfunction.

Hydraulic valves are calibrated at this time. The pressure gauge is inserted downstream, after the valve, and the valve is opened. Note the pressure reading.

Once the block is filled, the valve is switched to automatic. If the pressure reading drops, the screw on the pilot is turned slowly in a clockwise direction. If the pressure rises, the screw on the pilot has turned anticlockwise. The process is repeated by adjusting the pilot, checking the pressure again after a while, and adjusting the pilot again if necessary.

Once the hydraulic valves have been calibrated, the pressures in the lateral lines can be checked. Check the pressure at the end of each lateral which should be close to the pressure that the valve is set at. Alternatively, each lateral can be assessed visually and the pressure of the laterals measured appears to have a different distribution pattern than the other lines. Emitter delivery can also be checked to see if it corresponds with the irrigation plan. Place the emitter in a suitable container.

After a specific time (this may be 1 minute up to 30 minutes), remove the container and measure the amount of water. Calculate the emitter delivery per hour. When this test is done with a representative sample for the whole block, the CU (Coefficient of Uniformity) could be calculated. At least 30 measurements, spread out over the block, need to be done for this test. A Cu of 90% or more is good. A qualified irrigation technician should carry out CU tests as it needs good judgement and statistical calculations.

After this test is done and the system has been operating for a couple of days, the joints must be inspected for leaks. If no leaks are found, the trenches can be backfilled completely.