Virginia Residential Plumber

Flow pressure is measured while the faucet or outlet is wide open and flowing, whereas static pressure is measured when no flow is occurring.

Developed length follows the actual centerline path of the pipe including all fittings, while straight-line distance is simply the direct point-to-point measurement.

A vent with developed length of 40 feet or less may remain at minimum size, but a vent exceeding 40 feet must be increased one nominal pipe size for its entire length.

Renewal costs $160 and is available up to 30 days after expiration, whereas reinstatement costs $210 (non-refundable) and is required once the 30-day grace period has passed.

A Class A contractor performs or manages work valued at $150,000 or more on a single contract or $1 million or more within any 12-month period, thresholds that lower classifications do not meet.

Reduced pressure principle assemblies must be tested at installation, after repairs or relocation, and at least annually, while air gaps require only annual inspection to confirm the gap exists.

Piping previously used to convey nonpotable water is permanently prohibited from being reused for potable water regardless of disinfection, whereas new piping may carry potable water once properly installed.

A DWV air test requires 5 psi held for at least 15 minutes (not to be used on plastic), while a water supply test requires pressure not less than the system working pressure held for at least 15 minutes.

A threaded cleanout opening cannot be used to add a fixture or extend piping unless an equal-size cleanout is added, whereas a removable fixture P-trap with slip or ground joints is an accepted cleanout equivalent without that restriction.

Steel shield plates of not less than No. 16 gage are required when non-cast-iron or non-galvanized-steel piping passes within 1¼ inches of the nearest edge of a stud, joist, or rafter; no shield is required when the pipe is farther than 1¼ inches from any edge.

A felony or qualifying misdemeanor conviction (e.g., theft, drug distribution, sexual offense) must be reported in writing to the Virginia Board within 30 days of conviction, while a change of address must also be reported in writing within 30 days of the change — both deadlines are identical but triggered by different events.

These are unrelated limits that are commonly confused on exams: water from a tankless heater for domestic use must not exceed 140°F, whereas a pipe-applied vacuum breaker must be installed not less than 6 inches above the flood level rim of the fixture served.