Waters Protection Ordinance
(WPO)

¹ The au­thor­it­ies shall au­thor­ise the dis­charge of pol­luted waste wa­ter in­to sur­facewa­ters, drain­age areas, un­der­ground rivers and streams if the re­quire­ments on dis­charge in­to wa­ters ac­cord­ing to An­nex 3 are com­plied with.

² They shall set ad­di­tion­al or stricter re­quire­ments, if:

a.

the wa­ters con­cerned by the dis­charge of waste wa­ter do not ful­fil wa­ter qual­ity re­quire­ments ac­cord­ing to An­nex 2 or if this is ne­ces­sary to com­ply with in­ter­na­tion­al agree­ments or de­cisions; and

b.

on the basis of in­vest­ig­a­tion (Art. 47) it is cer­tain that de­fi­cient wa­ter qual­ity is largely due to dis­charge of waste wa­ter, and pro­ced­ures ne­ces­sary to com­ply are not dis­pro­por­tion­ate for the waste wa­ter treat­ment plant.

³ They may set ad­di­tion­al or stricter re­quire­ments if the wa­ter qual­ity ac­cord­ing to An­nex 2 is not suf­fi­cient for a spe­cif­ic use of the body of wa­ter con­cerned.

⁴ They may ap­ply less strin­gent re­quire­ments if:

a.

by re­du­cing the amounts of waste wa­ter dis­charged, few­er po­ten­tial wa­ter pol­lut­ants are dis­charged even though the con­cen­tra­tions al­lowed are high­er; or

b.

the en­vir­on­ment as a whole is less im­paired by the dis­charge of non-re­cyc­lable sub­stances in in­dus­tri­al waste wa­ter than by an­oth­er meth­od of dis­pos­al; re­quire­ments on wa­ter qual­ity ac­cord­ing to An­nex 2 and in­ter­na­tion­al agree­ments or de­cisions must be com­plied with.