[HCD 1] Each water purveyor that sells, leases, rents, furnishes, or delivers water service to a newly constructed multiunit residential structure or residential portion of newly constructed mixed-use residential and commercial structure for which an application for a water connection(s) is submitted after January 1, 2018, shall require a measurement of the quantity of water supplied to each individual residential dwelling unit as a condition of new water service. The measurement may be by individual water meters or submeters. See California Water Code Section 517 for definitions of "multiunit residential structure, " "mixed-use residential and commercial structure," and "submeter," and Section 537 et seq. for additional details and a list of exempted structures. See also the California Civil Code, Title 5, Part 4, Division 4, Chapter 2.5 (commencing with Section 1954.201).