Master Plumber Exam Study Guide 2026

BTU = gallons × 8.33 lb/gal × ΔT = 40 × 8.33 × 70 ≈ 23,324 BTU.

Both the International Plumbing Code (IPC) and the Uniform Plumbing Code (UPC) generally require cleanouts for horizontal drains to be installed at intervals not exceeding 100 feet. Some local codes may have different requirements, but 100 feet is the most common standard referenced in the major model codes.

The FHR measures how many gallons of hot water a heater delivers per hour starting with a full, hot tank — the key metric for sizing to peak demand.

Brand names, psi ratings, and nominal pipe sizes are necessary. Some pipe manufacturers offer measurement in one foot increments when rolls of pipe are 100' or greater, but do not indicate increments on joints of 21', 20', or less.

A stack vent is the extension of a soil or waste stack above the highest horizontal drain connection, serving as both the terminal of the drainage stack and as a vent.

The size of the drain pipe determines the grade, also known as pitch or fall, for the drain pipe. These plumbing system components are created by master plumbers and other design experts based on the minimal requirements set out by local codes. As a general rule,.25 inch per liner foot of slope is required for a drain with a diameter up to 4 inches.