All appeals are dismissed.

The costs of appeal are assessed against the Defendants.

The grounds of appeal are examined.

1. As to the ground of appeal No. 1, adding Article 35(1) of the former Enforcement Decree of the Sewerage Act (amended by Presidential Decree No. 25478, Jul. 16, 2014; hereinafter the same) to “construction, expansion, or alteration of use of a building, etc.” to “the volume of sewage discharged into a public sewerage system” to “the volume of sewage discharged into a public sewerage system” is deemed to have been commercialized based on the purport of Article 61(1) of the former Sewerage Act (amended by Act No. 11915, Jul. 16, 2013; hereinafter the same) as the mother corporation, and does not seem to have exceeded the regulatory scope

The ground of appeal pointing this out on a different premise is unacceptable.

2. Regarding ground of appeal No. 2

A. Article 61(1) of the former Sewerage Act provides that a public sewerage management authority may require the owners of buildings, etc. that can discharge sewage of more than the quantity prescribed by Presidential Decree into a public sewerage system to fully or partially bear the cost of rebuilding the public sewerage system. Article 35(1) of the former Enforcement Decree of the same Act provides that "the owners of buildings, etc. that can discharge sewage of more than the quantity prescribed by Presidential Decree into a public sewerage system" means those who newly construct, expand, or alter the use of buildings, etc. to discharge or increase sewage of more than 10 cubic meters per day by newly constructing, expanding, or altering the use of buildings, etc., and also require more than 10 cubic meters of wastewater to be newly discharged or increased by at least 10 cubic meters per day by delegation under Article 61(3) of the former Sewerage Act.

In addition, Article 61 (1) of the Sewerage Act amended by Act No. 11915 of July 16, 2013 is not less than the amount prescribed by Presidential Decree due to new construction or alteration of use of buildings.