How to find your backflow assembly

If you got a testing letter but aren't sure what it's talking about, you're not alone. A backflow prevention assembly is a brass or bronze fixture — usually about the size of a forearm — with two shutoff valves and a few small capped ports (called test cocks) sticking out. Here's what one typically looks like:

Where to look

Most residential assemblies are tied to an irrigation or sprinkler system, so start where that line leaves the house. Common spots:

• Outdoors along the foundation, near the water meter
• In a garden bed or against an exterior wall, sometimes under an insulated cover in winter
• Inside a green in-ground box near the sidewalk or property line
• In the garage, crawlspace, basement, or a mechanical room

Can't find it? That's fine

You don't need to locate the assembly yourself to book a test. Any OHA-certified tester can find it as part of the visit — just mention on the call that you're not sure where yours is, and roughly when your irrigation system was installed. If you want to confirm you even have one on record, the Portland Water Bureau can tell you what's on file for your address.