Section 43. Qualifications

All members of such board shall be citizens and
  actual residents of the cities in which they are  appointed,  except  in
  the  city  of  Niagara  Falls  where  such members shall be citizens and
  actual residents of the county wherein the city is situated, and  except
  in  the  city of Corning where such members shall be citizens and actual
  residents of the county wherein the city is situated or in  an  abutting
  or  adjacent  county,  and  except  in  the city of Rochester where such
  members shall be citizens and actual residents of the county wherein the
  city is situated, and except in the city of Watertown where such members
  shall be citizens and actual residents of the county wherein the city is
  situated. Provided however, in any city with a population of  less  than
  twenty-five  thousand,  or  in  any city which has less than four master
  plumbers, such members may  be  residents  of  the  county  or  counties
  wherein the city is situated.