D.C. Mun. Regs. tit. 25-C, § 6457
6457.1 Within the parameters specified in section 6456, the Department of Health shall prioritize and conduct more frequent inspections based upon its assessment of a swimming pool or spa facility's history of compliance with these regulations and its potential as a vector for waterborne illness by evaluating:
(a) Past performance for numerous or repeat critical violations of these regulations;
(b) Past performance for numerous or repeat violations of these regulations that are noncritical violations;
(c) Past performance, for complaints investigated and found to be valid; and
(d) The type of swimming pool or spa facility.
SOURCE: Final Rulemaking published at 55 DCR 012845 (December 26, 2008).