A backflow prevention assembly test report is a short document with a lot riding on it. The water purveyor uses it to decide whether an assembly stays in service, and a report that is incomplete, taken with an out-of-calibration gauge, or scored against the wrong values gets rejected — usually after the tester has left the site. The form itself is simple. What is not simple is knowing which readings a given assembly takes and what each one has to clear.
The most common error in circulation concerns the reduced pressure assembly. A great many published procedures and training notes still tell testers that check valve number one must sit a full 3.0 psid above the relief valve opening point. That buffer was removed from the USC field test procedure in the Tenth Edition, and the Foundation said so plainly in 2015: the review committee concluded the buffer was not an indication of the assembly’s ability to prevent backflow. It survives in Chapter 10 as part of the Standard, which governs approval, not as something a tester applies in the field. Anyone still failing assemblies on a 3.0 psid buffer is working from Ninth Edition practice.
The second thing worth being careful about is that these thresholds are not uniformly national. The USC values are what most purveyors adopt, but adoption is a local decision and some publish their own — Los Angeles County, for one, does not enforce the 5.0 psid floor on a reduced pressure first check. A tool that hardcodes the USC number would stamp FAIL on an assembly the local authority accepts, which is worse than useless to the tester holding it. So the threshold is yours to set, and whatever you set is printed on the report next to the verdict. A reviewer should never have to guess which standard a pass was reached under.