More stringent treatment had to be in place by 1998 for all discharges from agglomerations with a population equivalent of more than 10 000, discharging into sensitive areas and their catchments.
Reovee põhjalikum puhastamine pidi olema tagatud 1998. aastaks kõigis üle 10 000 inimekvivalendiga linnastutes, kus juhitakse reovesi tundlikele aladele ja nende valglatele.