Both the Commission and the principal councils, when carrying out their duties, are required by the Act to seek to ensure effective and convenient local government.
Yn ôl y Ddeddf, mae'n ofynnol i'r Comisiwn a'r prif gynghorau, wrth gyflawni eu dyletswyddau, geisio sicrhau llywodraeth leol effeithiol a chyfleus.