The Minnesota Building Codes and Standards Division has recently received several inquiries concerning installation of drain/waste piping on-site under manufactured homes.
Question #1: Are drain/waste systems under new manufactured homes allowed to be shipped without being connected under the new manufactured homes?
Answer: Yes in accordance with Code of Federal Regulations (C.F.R.), 3280.610(e)(5), "Sections of the drain system, designed to be located underneath the home, are not required to be factory installed when the manufacturer designs the system for site assembly and also provides all materials, components, including piping, fittings, cement, supports, and instructions necessary for proper site installation." On new manufactured homes the manufacturer shall supply all materials and a Design Inspection Primary Inspection Agency (DAPIA) approved drawing indicating how the drain system is to be completed on site. Also note, C.F.R. 3280.610(c)(1, 2, & 4), that a manufactured home shall have only one (1), three inch drain outlet.
Question #2: Is it acceptable to block/support drain lines under the manufactured home with concrete blocks lying on the ground?
Answer: No, in accordance with C.F.R. 3280.680(b) and (c)(1, 2, & 3), plastic drainage piping shall be supported at intervals not to exceed 4 feet, and piping shall be securely attached to the structure by hangers, clamps, or brackets which shall not compress, distort, cut, or abrade the piping.
Question #3: What ABS or PVC materials are allowed to be used for drain/waste lines under a manufactured home?
Answer: In accordance with C.F.R. 3280.604(b), ABS materials marked ASTM D-2661-91, ASTM D3311-91, and ASTM F-628-91 and PVC materials marked ASTM D2665-91b, may be used under new manufactured homes for drain/waste lines. If you are reworking or reinstalling a used manufactured home the above referenced materials may be used and Minnesota Plumbing Code 4715.0580 also allows ABS marked ASTM F628 and PVC marked ASTM F891, or D2949 or D1785 or D2241. (Installation shall be in accordance with referenced codes and applicable material standard."
Question #4: Are Licensed Manufactured Home Installers required to file a $25,000.00 Plumbing Code Compliance Bond with the Minnesota Department of Health, Plumbing Code Division when including building drain and water connections in installation contracts for manufactured homes.
Answer: No, if the only work being completed by the licensed manufactured home installer is the installation of the building drain and connection to the building sewer, and the installation of the water distributing pipe connection to the water service pipe. The installation of the building sewer and water service and any other plumbing shall be performed by any person(s) who have provided evidence of the $25,000 plumbing code compliance bond. Plumber licensure or pipelayer certification may be required for persons performing plumbing or the installation of water service or building sewer piping in cities with a population of 5,000 or greater.
Note the following definitions from Minnesota Plumbing Code, Chapter 4715.0100.
Subp. 24. Building drain. "Building drain" means that part of the lowest piping of the drainage system which received the discharge from soil, waste, and other drainage pipes inside the walls of the building and conveys it to the building sewer beginning at least one foot outside the building footings.
Subp. 27. Building sewer. "Building sewer" means that part of the drainage system which extends from the end of the building drain and conveys its discharge to the public sewer, private sewer, individual sewage-disposal system or other point of disposal.
Subp. 123. Water distributing pipe. "Water distributing pipe" means a pipe conveys water from the water service pipe to the point of usage.
Subp. 125. Water service pipe. "Water service pipe" means the pipe from the water main or other source of water supply to the water distributing system of the building served.