CSLB C-36 Plumbing ContractorFixture and Appliance InstallationMedium
A plumber is installing a new residential toilet. The rough-in dimensions specify a distance of 12 inches from the finished wall to the center of the closet flange. During installation, the plumber discovers that the existing waste pipe is only 10 inches from the finished wall. The client insists on using the chosen toilet model, which is a standard 12-inch rough-in. Which of the following is the most appropriate solution to ensure proper toilet installation and function?
- AInstall an offset closet flange to achieve the correct rough-in.
- BUse a flexible toilet supply line to bridge the difference.
- CInstall shims under the toilet to position it further from the wall.
- DChip away at the finished wall behind the toilet to gain space.
Show answer & explanationAnswer & explanation
Correct answer: A. Install an offset closet flange to achieve the correct rough-in.
An offset closet flange is specifically designed to adjust the position of the toilet's waste outlet relative to the existing drain pipe, allowing a standard 12-inch rough-in toilet to be installed on a 10-inch rough-in drain.
Why the other options are wrong
- B. A flexible supply line connects water, not the waste outlet, and does not affect the rough-in distance.
- C. Shims under the toilet would raise it, not move it horizontally to adjust the rough-in distance.
- D. Chipping the wall is an unprofessional and structurally unsound solution for a rough-in discrepancy.
Offset Closet Flange
An offset closet flange is a drain fitting that allows the toilet's waste outlet to be shifted horizontally by a small amount (typically 1 to 2 inches) to accommodate variations in rough-in dimensions between the toilet and the existing waste pipe.
- Adjusts toilet rough-in distance.
- Used for minor discrepancies.
- Essential for proper toilet alignment.
Memory trick: When the rough-in's off, an offset flange will fix the scoff.