Section 18.60.705 - Plumbing code(a) Except as provided otherwise in this section, and unless the department adopts by regulation a later edition of the following publications or a later version of another nationally recognized code approved by the legislature by law, the following publications are adopted as the minimum plumbing code for the state: (1) paragraphs 101.3 - 101.5.6, 103.5.1.1 - 103.5.1.4, 103.5.3.5, 103.5.4.2, 103.5.5.1 - 103.5.5.2, 103.5.6.1 - 103.5.6.3, and 103.8 - 103.8.2 of chapter 1, chapters 2 - 14, and the appendices A through L of the 1997 edition of the Uniform Plumbing Code published by the International Association of Plumbing and Mechanical Officials and adopted at the 67th annual conference, September 1996, excluding Table 4.1, "Minimum Plumbing Facilities"; and adding Appendix Chapter 29, Table A - 29 - A, "Minimum Plumbing Fixtures," of the 1997 edition of the Uniform Building Code published in April 1997 by the International Council of Building Officials, except that for the category identified in Table A - 29 - A as "Assembly places-Auditoriums, convention halls, dance floors, lodge rooms, stadiums and casinos," when the category is applied to auditoriums, convention halls, stadiums, and casinos, the ratios (A) indicating the number of water closets required for females are changed to provide the following: (i) four water closets for 1 - 50 females;(ii) six water closets for 51 - 100 females;(iii) 10 water closets for 101 - 200 females;(iv) 14 water closets for 201 - 400 females; and(v) one additional water closet for each 100 females over 400 females; and(B) indicating the number of lavatories required for females and males are changed to (i) one lavatory for each water closet up to four water closets; and(ii) one additional lavatory for each two additional water closets beyond four water closets;(2) the 1997 edition of the Uniform Swimming Pool, Spa, and Hot Tub Code published by the International Association of Plumbing and Mechanical Officials and adopted at the 67th annual conference, September 1996, excluding pages 1 - 8 of Part I, Administration; and(3) the 1997 edition of the Uniform Solar Energy Code published by the International Association of Plumbing and Mechanical Officials and adopted at the 67th annual conference, September 1996, excluding pages 1 - 7 of Part I, Administration.(b) Notwithstanding (a) of this section, the use of a pipe or pipe fitting containing more than 8.0 percent lead, or of solder or flux containing more than 0.2 percent lead in the installation or repair of a public water system or in the installation or repair of plumbing of a residential or nonresidential facility that provides water for human consumption is prohibited. This subsection does not apply to the use of leaded joints necessary to repair cast iron pipe.(c) Notwithstanding (a) of this section, a single-wall heat exchanger may be used if (1) the heat transfer medium is water type or propylene type glycol;(2) the pressure of the heat transfer medium is limited to a maximum of 30 pounds per square inch by an approved safety relief valve; and(3) the heat exchanger is prominently and permanently labeled with instructions concerning (1) and (2) of this subsection.