What is code for stair treads and risers in Georgia
It looks like Georgia revises its building code frequently.  I didn't find a revision for 2005, but the 2006 edition was OCR scanned and published here.

In section 1009.3, there is this:


  1009.3 Stair treads and risers Stair riser heights shall be 7 
  inches (178 mm) maximum and 4 inches (102 mm) minimum. 
  Stair tread depths shall be 11 inches (279 mm) minimum. The 
  riser height shall be measured vertically between the leading 
  edges of adjacent treads. The tread depth shall be measured 
  horizontally between the vertical planes of the foremost projection of adjacent treads and at a right angle to the tread's leading 
  edge. Winder treads shall have a minimum tread depth of 11 
  inches (279 mm) measured at a right angle to the tread's leading edge at a point 12 inches (305 mm) from the side where the 
  treads are narrower and a minimum tread depth of 10 inches 
  (254 mm).


(I have cleaned up OCR defects.)