The judgment below is reversed and the case is remanded to Seoul High Court.

The grounds of appeal are examined.

1. Where it is not clear whether a provision of an enforcement decree or municipal ordinance conflicts with the mother law, if it is possible to interpret that provision is consistent with the mother law by comprehensively examining the other provisions of the mother law, the Enforcement Decree or municipal ordinance, its legislative intent, history, etc., the provision shall not be declared null and void as a violation of the mother law.

This legal principle, along with the principle that the legal system of the state itself forms a unified body, the conflict between the upper and the upper rules should be excluded to the maximum extent, is based on the presumption principle that the norm in the democratic state generally conforms to the upper rules, and in the case where the lower rules are declared invalid as it goes against the upper rules, not only the legal confusion and legal instability due to them, but also the legal gap and legal protection until the new rules replacing them are enacted are considerably serious, so it is also necessary to avoid such harm.

(2) The former Water Supply and Waterworks Installation Act (wholly amended by Act No. 8370, Apr. 11, 2007; Act No. 10317, May 25, 201; hereinafter “former Water Supply and Waterworks Installation Act”) (see, e.g., Supreme Court Decisions 2000Du2716, Aug. 24, 2001; 201Du3527, Oct. 25, 201); 2. Article 71(1) of the former Water Supply and Waterworks Installation Act (wholly amended by Act No. 8370, Apr. 11, 2007; hereinafter “former Water Supply and Waterworks Installation Act”) provides that “A waterworks business operator may bear all or part of expenses incurred in performing waterworks works (including a person who has caused new construction or extension, etc. of waterworks facilities, such as a housing complex or industrial facilities), or a person who has damaged waterworks, with the standards for calculating charges under paragraph (1).”