{"data":{"id":"us/24-cfr-3280.602","jurisdiction":"us","citation":"24 CFR 3280.602","heading":"Definitions.","body":"The following definitions are applicable to subpart G only:\nAccessible, when applied to a fixture, connection, appliance or equipment, means having access thereto, but which may require removal of an access panel or opening of a door.\nAir gap (water distribution system) means the unobstructed vertical distance through the free atmosphere between the lowest opening from any pipe or faucet supplying water to a tank, plumbing fixture, water supplied appliances, or other device and the flood level rim of the receptacle.\nBackflow means the flow of water or other liquids, mixtures, or substances into the distributing pipes of a potable supply of water from any source or sources other than its intended sources.\nBackflow connection means any arrangement whereby backflow can occur.\nBackflow preventer means a device or means to prevent backflow.\nBranch means any part of the piping system other than a riser, main or stack.\nCommon vent means a vent connecting at the junction of fixture drains and serving as a vent for more than one fixture.\nContinuous vent means a vertical vent that is a continuation of the drain to which it connects.\nContinuous waste means a drain from two or more fixtures connected to a single trap.\nCritical level means a point established by the testing laboratory (usually stamped on the device by the manufacturer) which determines the minimum elevation above the flood level rim of the fixture or receptacle served on which the device may be installed. When a backflow prevention device does not bear a critical level marking, the bottom of the vacuum breaker, combination valve, or of any such approved or listed device shall constitute the critical level.\nCross connection means any physical connection or arrangement between two otherwise separate systems or sources, one of which contains potable water and the other either water, steam, gas or chemical of unknown or questionable safety whereby there may be a flow from one system or source to the other, the direction of flow depending on the pressure differential between the two systems.\nDeveloped length means that length of pipe measured along the center line of the pipe and fittings.\nDiameter, unless otherwise specifically stated, means the nominal (inside) diameter designated commercially.\nDrain means a pipe that carries waste, water, or water-borne waste in a drainage system.\nDrain connector means the removable extension, consisting of all pipes, fittings and appurtenances, from the drain outlet to the drain inlet serving the manufactured home.\nDrain outlet means the lowest end of the main or secondary drain to which a sewer connection is made.\nDrainage system means all piping within or attached to the structure that conveys sewage or other liquid waste to the drain outlet, not including the drain connector.\nFixture drain means the drain from the trap of a fixture to the junction of that drain with any other drain pipe.\nFixture supply means the water supply pipe connecting a fixture to a branch water supply pipe or directly to a main water supply pipe.\nFlood-level means the level in the receptacle over which water would overflow to the outside of the receptacle.\nFlooded means the condition which results when the liquid in a container or receptacle rises to the flood-level.\nFlush tank means that portion of a water closet that is designed to contain sufficient water to adequately flush the fixture.\nFlush valve means a device located at the bottom of a flush tank for flushing a water closet.\nFlushometer tank: means a device integrated within an air accumulator vessel which is designed to discharge a predetermined quantity of water to fixtures for flushing purposes.\nFlushometer valve means a device which discharges a predetermined quantity of water to a fixture for flushing purposes and is closed by direct water pressure.\nGrade means the fall (slope) of a pipe in reference to a horizontal plane expressed in inches per foot length.\nHorizontal branch means any pipe extending laterally, which receives the discharge from one or more fixture drains and connects to the main drain.\nHorizontal pipe means any pipe or fitting which makes an angle of not more than 45 degrees with the horizontal.\nIndirect waste receptor means a receptor that receives a discharge waste pipe that is not directly connected to a receptor but maintains a suitable air gap between the end of the pipe and the top of the drain.\nIndividual vent means a pipe installed to vent a fixture drain.\nInlet coupling means the terminal end of the water system to which the water service connection is attached. It may be a swivel fitting or threaded pipe end.\nMain means the principal artery of the system to which branches may be connected.\nMain drain means the lowest pipe of a drainage system which receives sewage from all the fixtures within a manufactured home and conducts these wastes to the drain outlet.\nMain vent means the principal artery of the venting system to which vent branches may be connected.\nMechanical trap vent device means a device that automatically opens to admit air to a fixture drain above the connection of the trap arm so as to prevent siphonage, and closes tightly when the pressure within the drainage system is equal to or greater than atmospheric pressure, so as to prevent the escape of gases from the drainage system into the manufactured home.\nOffset means a combination of pipe and/or fittings that brings one section of the pipe out of line but into a line parallel with the other section.\nPitch. See Grade.\nPlumbing appliance: means any one of a special class of plumbing fixture which is intended to perform a special plumbing function. Its operation and/or control may be dependent upon one or more energized components, such as motors, control, heating elements, or pressure or temperature-sensing elements. Such fixture may operate automatically through one or more of the following actions: A time cycle, a temperature range, a pressure range, a measured volume or weight, or the fixture may be manually adjusted or controlled by the user or operator.\nPlumbing appurtenance: means a manufactured device, or a prefabricated assembly, or an on-the-job assembly of component parts, and which is an adjunct to the basic piping system and plumbing system and plumbing fixtures. An appurtenance demands no additional water supply, nor does it add any discharge load to a fixture or the drainage system.\nPlumbing fixtures means receptacles, devices, or appliances which are supplied with water or which receive liquid or liquid-borne wastes for discharge into the drainage system.\nPlumbing system means the water supply and distribution pipes; plumbing fixtures, faucets and traps; soil, waste and vent pipes; and water-treating or water-using equipment.\nPrimary vent. See main vent.\nRelief vent means an auxiliary vent which permits additional circulation of air in or between drainage and vent systems.\nSecondary vent means any vent other than the main vent or those serving each toilet.\nSewage means any liquid waste containing animal or vegetable matter in suspension or solution, and may include liquids containing chemicals in solution.\nSiphonage means the loss of water seal from fixture traps resulting from partial vacuum in the drainage system which may be of either of the following two types, or a combination of the two:\n(a) Self-siphonage resulting from vacuum in a fixture drain generated solely by the discharge of the fixture served by that drain, or,\n(b) Induced siphonage resulting from vacuum in the drainage system generated by the discharge of one or more fixtures other than the one under observation.\nTrap means a fitting or device designed and constructed to provide a liquid seal that will prevent the back passage of air without materially affecting the flow of liquid waste through it.\nTrap arm means the portion of a fixture drain between a trap and its vent.\nTrap seal means the vertical depth of liquid that a trap will retain.\nVacuum breaker. See backflow preventer.\nVent cap means the device or fitting which protects the vent pipe from foreign substance with an opening to the atmosphere equal to the area of the vent it serves.\nVent system means that part of a piping installation which provides circulation of air within a drainage system.\nVertical pipe means any pipe or fitting which makes an angle of not more than 45 degrees with the vertical.\nWater closet drain means that part of the drainage piping which receives the discharge from each individual water closet.\nWater connection means the fitting or point of connection for the manufactured home water distribution system designed for connection to a water supply.\nWater connector means the removable extension connecting the manufactured home water distribution system to the water supply.\nWater distribution system means potable water piping within or permanently attached to the manufactured home.\nWet vent means a vent which also serves as a drain for one or more fixtures.\nWet vented drainage system means the specially designed system of drain piping that also vents one or more plumbing fixtures by means of a common waste and vent pipe.\nWhirlpool bathtub means a plumbing appliance consisting of a bathtub fixture which is equipped and fitted with a circulation piping system, pump, and other appurtenances and is so designed to accept, circulate, and discharge bathtub water upon each use.","path":["Title 24—Housing and Urban Development","Subtitle B—Regulations Relating to Housing and Urban Development","CHAPTER XX—OFFICE OF ASSISTANT SECRETARY FOR HOUSING—FEDERAL HOUSING COMMISSIONER, DEPARTMENT OF HOUSING AND URBAN DEVELOPMENT","PART 3280—MANUFACTURED HOME CONSTRUCTION AND SAFETY STANDARDS","Subpart G—Plumbing Systems"],"source_url":"https://www.ecfr.gov/api/versioner/v1/full/2026-08-25/title-24.xml","current_through":"2026-08-25","vintage":"","retrieved_at":"2026-08-27T02:24:55Z","sha256":"cf4f5d136346507171193cd7a309f7c0a7af13d63e19d65c8b3202ca2462bbcb","source_id":"us-cfr","stale":true,"prev":"us/24-cfr-3280.601","next":"us/24-cfr-3280.603"},"notice":"GroundRules: Original legal text. Not legal advice."}