Free-Flowing Pipes

Overhead sprinklers have a screen filter mounted under the drive assembly for rotors or under the nozzle for sprayheads, so they typically don’t need any additional filter placed along the piping network, says Mike Stoll, market manager for Netafim USA’s landscape and turf division, Fresno, Calif. But because drip systems are small, drip manufacturers must place a filter either close to the point of connection or by the zone valve operating the drip or dripper-line zone.

The most common filters in landscape applications are disk and screen filters. A screen filter is typically made from a polyester mesh or stainless steel, Stoll says. They only capture about 60 percent of what they’re designed to capture, but they’re relatively cost effective. A ¾-inch screen filter sells for $10 to $13 compared to $20 for a ¾-inch disk filter, according to Stoll. 

A disk filter has rings inside of the filter housing that “resemble poker chips with a hole in the middle and a striated surface on the top and bottom of each ring,” Stoll says. There is a stack of these rings in each filter. Water is squeezed through the ring surfaces, which capture more than 90 percent of what they’re designed to catch. “Because disk filters, also known as depth filtration are far more likely to catch contaminants than a more one-dimensional filter, they are clearly superior,” Stoll says.

Maintenance of the filters usually involves checking the filter screen or rings twice a year or more in dirty water conditions. “The best way to do that is to return to a new installation after a couple of weeks and while making sure the system is operating properly, check the filter for debris,” Stoll explains. “In a potable water system, it may be very clean and only need to be cleaned once or twice a year. If the filter is on a well or lake-fed system, it may be determined that the homeowner or property manager should clean it more frequently.”