Drip irrigation can be a powerful tool for water conservation but only if it’s used correctly. Despite the marketing hype, it’s definitely not a “set it and forget it” solution.
Often hailed as the most water-efficient method for watering landscapes, drip irrigation is much more nuanced than it seems.
In fact, when improperly designed, scheduled or maintained, drip systems can use just as much — if not more — water than traditional spray systems.
One of the most common drip configurations in the industry involves emitters spaced on a 12-inch by 12-inch grid delivering 0.9 gallons per hour. This configuration equates to a precipitation rate of approximately 1.44 inches per hour, more than three times that of a typical rotor zone and comparable to many spray zones. That’s a tremendous output, and if schedules aren’t matched to soil type and plant needs, it can lead to runoff, deep percolation and significant water waste.
Many users fail to consider the actual output of their system. Without understanding the precipitation rate, accurate scheduling is nearly impossible. For example, if your goal is to deliver just 0.25 inches of water per week (sufficient for well-established native plants) you’d only need to run this drip zone for 10 minutes once a week. Compare that to the common but misguided recommendation of 30 minutes, three times a week which would deliver 2.16 inches of water — nearly 10 times the plant’s actual needs!
So why is drip so often overscheduled? The issue usually isn’t the plant selection or the system configuration, but the soil.
The 1.44 in/hr output assumes ideal infiltration, but many soils in our region, especially highly compacted clay loams, can’t absorb water at that rate. Excess water quickly drains past the root zone, offering little benefit to the plant. Unlike sprays, which broadcast water over a wide area, drip systems rely on capillary action in the soil to move water sideways toward plant roots. If your soil can’t support this movement, adding more run time won’t help.
If probing the soil after a cycle reveals no lateral movement, don’t just increase your runtime. Instead, improve the soil. Amending with compost or organic matter increases porosity, boosts water retention, and enhances horizontal distribution, ensuring the water you apply is actually accessible to the plants.
Drip systems should also be paired with appropriate plant choices. Well-established, drought-tolerant native plants, when selected wisely, can often thrive with minimal to no supplemental irrigation. If you find yourself running drip lines several times per week for these species, it’s likely time to reevaluate your soil condition, irrigation schedule or plant palette.
Just as important as soil and scheduling is maintenance. Drip systems are especially vulnerable to damage. Tubing can be pierced by foot traffic, weed trimmers, or even chewed through by squirrels and rodents, causing hidden leaks that waste hundreds of gallons of water.
Because drip operates quietly and at low pressure, leaks often go unnoticed until your water bill spikes or plants show signs of stress. Routine inspections: checking for breaks, clogged emitters, or signs of animal damage, are essential. Even the best-designed system can fail if it’s not maintained.
Know your system’s output (typically drip systems can range from 0.47-1.44 in/ per hour), understand your soil’s limitations, select appropriate plants, and regularly inspect your system for damage.
Also, remember, that current Stage 3 watering rules restrict drip irrigation to Mondays and/or Fridays between the hours of 5-10 a.m. and/or 9 p.m.-midnight. So, if your water day is Tuesday, your drip zones should be scheduled on a separate program to accommodate the Monday/Friday drip schedule.
Of course, if you need help assessing and scheduling your drip and other irrigation zones, don’t forget that SAWS offers free irrigation consultations.
A highly-trained licensed irrigator will visit your home, evaluate your system and provide insights and advice on how to best schedule and maintain your system for optimal efficiency!
