D.C. Mun. Regs. tit. 25-D, § 716
716.1 A water filter, screen, or other water-conditioning device installed on water lines shall be located to facilitate disassembly for periodic servicing and cleaning.
716.2 Fill-and-drain whirlpool spa bathtub pumping and recirculation systems shall be treated with an effective biocide and scale-reduction agent as recommended by the manufacturer.
Source: Final Rulemaking published at 56 DCR 7975 (October 9, 2009).