D.C. Mun. Regs. tit. 12, r. 12-F305
Strike Section 305.4 of the International Plumbing Code in its entirety and insert a new Section 305.4 into the Plumbing Code in its place to read as follows:
Freezing.Water, soil and waste pipes shall not be installed outside of a building, in attics or crawl spaces, concealed in outside walls, or in any other place subjected to freezing temperatures unless adequate provision is made to protect such pipes from freezing by insulation or heat or both. Exterior water supply system piping shall be installed not less than 12 inches (305 mm) below the frost line and not less than 30 inches (762 mm) below grade.
Strike Section 305.4.1 of the International Plumbing Code in its entirety and insert new Section 305.4.1 in the Plumbing Code in its place to read as follows:
Sewer depth.Building sewers that connect to private sewage disposal systems shall be installed not less than 30 inches (762 mm) below finished grade at the point of septic tank connection. Building sewers shall be installed not less than 30 inches (762 mm) below grade at any point between the building foundation and the connection to the public sewer.
D.C. Mun. Regs. tit. 12, r. 12-F305