By reason of the fact that discharging of sewage or, sewage residue or sewage effluent into the water supply of the city, is or could be injurious to the health of the inhabitants of the city, the existence or the maintenance or operation of a sewage treatment plant or sewage disposal system, or a sewage lagoon draining sewage residue or sewage effluent into the source of water supply of the city is hereby declared a public nuisance.
(`90 Code, § 18-24)