We are often asked when to blowout and start sprinkler systems for the season. May 9th is a safe start date for spring and October 15th is good for shut down. Sprinkler systems can be quite expensive to repair if they freeze, so it is best to not start them too early in the spring.
Some companies charge extra for backyard valves, we thought it confusing and we said "no" to hidden costs. We often run specials for sprinkler blowout; current price is $44.00.