The county council shall consist of five members nominated and elected from districts. Councilmembers shall be residents and registered voters of the district they represent at the time of filing for election to said office and at all times during their terms. Any change in the boundaries of a councilmember’s district which shall cause the councilmember to be no longer a resident shall not disqualify the councilmember from holding office during the remainder of the term for which the councilmember was elected or appointed.