(a) An individual may be removed from office by address for:
(1) wilful neglect of duty;
(2) incompetency;
(3) habitual drunkenness;
(4) oppression in office;
(5) breach of trust; or
(6) any other reasonable cause that is not a sufficient ground for impeachment.
(b) In this section, "incompetency" means:
(1) gross ignorance of official duties;
(2) gross carelessness in the discharge of official duties;
(3) inability or unfitness to discharge promptly and properly official duties because of a serious physical or mental defect that did not exist at the time of the officer's election; or
(4) persistent or wilful violation of Article 17.15, Code of Criminal Procedure.