(a) The following definitions refer to water closets:

1. (1) Blowout toilet means a water closet that uses a non-siphonic bowl with an integral flushing rim, a trap at the rear of the bowl, and a visible or concealed jet that operates with a blowout action.
2. (2) Dual-flush effective flush volume means the average flush volume of two reduced flushes and one full flush.
3. (3) Dual-flush water closet is a water closet incorporating a feature that allows the user to flush the water closet with either a reduced or a full volume of water.
4. (4) Electromechanical hydraulic water closet means a water closet that utilizes electrically operated devices, such as, but not limited to, air compressors, pumps, solenoids, motors, or macerators in place of or to aid gravity in evacuating waste from the toilet bowl.
5. (5) Flushometer tank means a flushometer valve that is integrated within an accumulator vessel affixed and adjacent to a plumbing fixture inlet so as to cause an effective enlargement of the supply line immediately before the fixture.
6. (6) Flushometer tank water closet means a water closet utilizing a flushometer tank.
7. (7) Flushometer valve means a valve that is attached to a pressurized water supply pipe and that is designed so that when actuated it opens the line for direct flow into the fixture at a rate and predetermined quantity to properly operate the fixture, and then gradually closes in order to provide trap reseal in the fixture and to avoid water hammer. The pipe to which the device is connected is, in itself, of sufficient size that when open shall allow the device to deliver water at a sufficient rate of flow for flushing purposes.
8. (8) Gallons per flush (GPF) means gallons per flush as determined using the applicable test method.
9. (9) gravity tank-type water closet means a water closet that includes a storage tank from which water flows into the bowl by gravity.
10. (10) Prison-type water closet means a water closet designed and marketed expressly for use in prison-type institutions.
11. (11) Vacuum-type water closet means a water closet whose bowl is evacuated by the application of a vacuum.
12. (12) Water closet means a plumbing fixture having a water-containing receptor that receives liquid and solid body waste through an exposed integral trap into a gravity drainage system.

13. (13) Water use means the quantity of water flowing through a water closet or urinal at point of use, determined in accordance with test procedures under Appendix T of subpart B of 10 CFR part 430, as incorporated by reference in section 509.61 of this Part.

    (b) Standard requirements for water closets.

14. (1) The water consumption of water closets, other than those designed and marketed exclusively for use at prisons or mental health care facilities, shall be no greater than 1.28 gallons per flush or dual-flush effective flush volume.

    (c) Test procedures for assuring compliance with the standards established in subdivision (b) of this section.

15. (1) The test method for testing gallons per flush of water closets is 10 CFR section 430.23(u) (Appendix T to Subpart B of part 430), as incorporated by reference in section 509.61 of this Part. The waste extraction test method for water closets is section 7.10 of ASME A112.19.2/CSA B45.1-2013.