Old fashioned irrigation systems were quite thorough, and technically sustainable. They broadcast generous volumes of water over any vegetation that required it. Their systems were too simple to need much adjustment. Their metallic composition was very resilient. That is why so many old systems were in service for so long. Some continue to function.

However, such old fashioned irrigation systems were not perfect. Their consumption was not as sustainable as their plumbing. They wasted water on vegetation that needed less, and pavement. Some of the broadcast water evaporated before reaching any vegetation. Without automation, old irrigation systems operated when convenient for their operators.

Modern irrigation systems are typically more efficient. Automation allows them to operate prior to sunrise to limit evaporation. Most modern systems apply water directly to the soil. This leaves no irrigation water to evaporate from foliar or other surfaces. Also, it prevents evaporation from airborne broadcast irrigation water. Evaporation innately wastes water.

Of course, modern irrigation systems are no more perfect than old systems. Groundcover and lawns still rely on broadcast irrigation. Such systems still waste water on pavement. Automation can actually waste water if not adjusted manually for rain and other weather. Only the most modern automation adapts to weather. No system responds to vegetation.

Consequently, irrigation can become either deficient or excessive as vegetation matures. Many native species need regular irrigation only as they disperse roots after installation. They are likely to rot with the same irrigation as they mature. Many tropical species need more water as they grow. Some vegetation, as it grows, can obstruct broadcast irrigation.

The complexity of modern irrigation systems complicates their maintenance. Automation is merely one component of the infrastructure. Emitters of drip irrigation sometimes need relocation or replacement. They are sometimes difficult to find below healthy vegetation. Because components are plastic, they are not as durable as old fashioned components.