This is a photo of a backflow preventer which was taken during a home inspection performed by my company, Magpie Property Inspections, in Castle Rock Colorado. The backflow preventer is a device which is attached to the sprinkler system plumbing as an important safety feature.
Fresh water plumbing was tapped and routed to the exterior of this home as the source of water to irrigate the lawn and plants in the yard, via an underground sprinkler system. This is a normal practice for most home sprinkler systems in this area. Connecting the freshwater system to the sprinkler plumbing, however, provides the opportunity for water outside to re-enter the home’s freshwater plumbing, allowing outside contaminants into the water supply. This can present a very serious health concern. To keep this from occurring, this system has a backflow preventer in place between the fresh water line and water in the sprinkler system. Some backflow preventers may be located inside a valve box in ground and not visible like this one, so it is important to know where yours is and what it looks like.
The problem discovered during this home inspection is that this unit has become damaged, as you can see in the photo. If the system is not properly winterized and serviced, damage like this can occur from freezing. It may also begin to leak, or show signs of wear over time. It is important to make sure if you have a sprinkler system to know what your backflow preventer looks like, where it is located, and to check it frequently to make sure it is in good visual and working condition. If an issue develops with your system, or backflow preventer, make sure to have it repaired or replaced immediately by a qualified plumbing contractor or sprinkler service provider. If in doubt, have your system inspected and tested to be sure.