RPZ, DCVA, PVB, or AVB—get the full installed cost including device, labor, testing, and permits so your quote is airtight.
An AVB is $15–$40 and takes 30 minutes. An RPZ for a 2″ commercial main is $800–$2,500 and takes half a day. Know which hazard classification the AHJ requires before you price anything—a misjudged spec is a change order waiting to happen.
DCVA and RPZ assemblies must be tested by a certified tester after installation and annually thereafter. Bundle the first test into your install price—it's a 30–45 minute add-on that costs $75–$150 and prevents warranty disputes later.
Underground vault installations add excavation, concrete, a lid, drainage provisions, and significantly more labor. Price these at 2–3× an interior install of the same device size—and get a soil report if the site is near utilities.
The Plumber's Business Starter Kit includes a flat-rate price book for 40 common jobs (including backflow), a service agreement template, and a morning dispatch checklist. Guide from $19 — Complete Kit with all 19 templates, $49.
Get the Plumber's Kit →Backflow preventer installation is required by code in most jurisdictions for irrigation systems, boilers, and certain commercial connections — and it comes with permit and inspection costs that must be in your quote. This calculator prices the job based on backflow device type, connection size, labor time, and permit fees so you're covering all your costs.