2014 ASHS Annual Conference

A residential landscape plan was developed and drawn to scale.  The landscape included 465 m² of turfgrass, an 84 m² tree island and 45 m² of woody ornamentals. Thirty-one irrigation contractors were asked to bid on the installation of an irrigation system for the landscape and 11 bids were received. Five of the contractors were WaterSense^© (WS) partners.   Seven participating contractors were Irrigation Association (IA) certified.  The bids ranged from a high of $3,480 to a low of $1,530 with an average bid price of $2,417.  WS partner bids with an average cost of $2,297, were slightly lower than non-partner bids, which averaged $2,517 (no statistical different P=0.05).  The seven IA certified contractors (average = $2,549) tended to charge more than the four, non-certified contractors (average = $2,188), though the difference was not statistically significant. Some of the bids suggested practices that would increase water use.  For instance, two bids did not use drip irrigation on the woody ornamentals. Another bid watered the tree island, noting that installation would be less expensive if the tree island was watered with turfgrass areas. One contractor suggested eliminating the rain shutoff devise to save money (this is a violation of state law).   Six contractors included WS labeled smart controllers in the bids, only two of these contractors were WS partners. One bid provided no information regarding the controller and four bids provided no information about nozzles, heads or drip equipment.   Only one bid provided water saving, equipment upgrade options for the consumer, yet did not specify that the upgrades would reduce water use. Many consumers must pay for water the irrigation system uses as well as installation costs.  Ongoing water costs may quickly eclipse the cost of the installation.  Results suggest contractors may be able to distinguish their bids and sell upgrades by including estimated water costs in bids and conversation.