Section 13558.1 - Installation of onsite treated nonpotable water system(a) An onsite treated nonpotable water system shall not be installed except under a program established in compliance with subdivision (b) of Section 13558.(b) This section does not apply to untreated graywater systems that are used exclusively for subsurface irrigation that are regulated by Chapter 15 (commencing with Section 1501.0) of the California Plumbing Code (Part 5 of Title 24 of the California Code of Regulations).(c) This section does not apply to untreated rainwater systems that are used exclusively for surface, subsurface, or drip irrigation that are regulated by Chapter 16 (commencing with Section 1601.0) of the California Plumbing Code (Part 5 of Title 24 of the California Code of Regulations).Added by Stats 2018 ch 890 (SB 966),s 1, eff. 1/1/2019.