Misty landscape? It’s the in-ground sprinklers screaming they’re under too much pressure.
You’ve probably seen it before, clouds of foggy mist spewing from the in-ground sprinkler system like an aerosol can. The problem is most of that mist ends up withering away into oblivion, watering the air instead of benefiting your landscape.
It’s called high pressure and there’s a reason SAWS irrigation consultants recommend fixing the problem with pressure-regulated sprinkler heads. They not only conserve water, but also improve the entire system’s performance.
Typical sprinkler heads are designed for a running pressure of 30 pound-force per square inch or psi (45 for rotors.) If your SAWS irrigation consultant tells you the pressure is too high (in some cases 70 psi or more) then your sprinklers are vastly exceeding their design range and putting out much more water than intended, sometimes twice as much.
You’d think higher pressure would be better. But unfortunately, pushing more water through a pinhole doesn’t necessarily result in better coverage. It results in mist, instead of large drops that reach the ground. This ends up degrading irrigation efficiency, despite the increase in volume. In addition to the telltale fog and wind drift, it leaves behind visible dry patterns in the lawn — meaning longer run times and even more water waste.
One of the simplest fixes for high pressure is regulating it at the heads by replacing every single internal body on an entire irrigation zone. The result is better distribution uniformity and sometimes considerable water savings. For instance, a 10 percent pressure reduction at the spray head can equal about ½ gallon of water savings per head per minute. Taking 10 sprays per station as average, that could equal about 5 gallons per minute per station. If you have a current run time of 12 minutes, that’s 60 gallons of water per station. (For a typical home with about six stations, in spring the savings could reach 360 gallons per weekly watering cycle, or 1,440 gallons per month!)
Not all sprinkler heads are created equally. Pressure-regulated sprinkler heads are typically labeled with “PRS” on the top collar. Picking the right sprinkler head requires an understanding of your existing system and its pressure requirements. Consult a licensed irrigator or a professional irrigation supplier for more information, especially in cases of very high pressure which call for very specific products.
SAWS offers a residential irrigation rebate for converting an entire qualifying zone to pressure-reducing heads. Call 210-704-SAVE to schedule a free an irrigation consultation to see if your system is eligible.
