Na [[Unión Europea]], aprobouse a Directiva do Consello 91/271/EEC sobre Tratamento de Augas Residuais Urbanas o 21 de maio de 1991,<ref>http://eur-lex.europa.eu/LexUriServ/LexUriServ.do?uri=CELEX:31991L0271:EN:NOT</ref> amended by the Commission Directive 98/15/EC.<ref>http://eur-lex.europa.eu/LexUriServ/LexUriServ.do?uri=CELEX:31998L0015:EN:NOT</ref>
{{Main|Directive on Urban Waste Water Treatment}}
Councile Directivea 91Decisión a Comisión 93/271481/EEC ondefine Urbana Wastewaterinformación Treatmentque wasos adoptedestados onmembros 21deberían Mayproporcionar 1991,<ref>http://eur-lex.europa.eu/LexUriServ/LexUriServ.do?uri=CELEX:31991L0271:EN:NOT</ref>á amendedComisión bysobre theo Commissionestado Directivede 98/15/ECaplicación da Directiva.<ref>http://eur-lex.europa.eu/LexUriServ/LexUriServ.do?uri=CELEX:31998L001531993D0481:EN:NOT</ref>
Commission Decision 93/481/EEC defines the information that Member States should provide the Commission on the state of implementation of the Directive.<ref>http://eur-lex.europa.eu/LexUriServ/LexUriServ.do?uri=CELEX:31993D0481:EN:NOT</ref>
