According to the Census Bureau's year-to-date total through April 2013, the most active counties for single-family permits in Colorado, when adjusted for each County's total household numbers, were Douglas, Broomfield, Weld, El Paso, and Larimer counties.
All counties, when adjusted for the existing number households in each county: (New single-family permits per household (x1,000)):
El Paso 4.0
Of the 4,339 new single-family permits issued this year through April, more than two-thirds of them (67 percent) were issued in Arapahoe, El Paso, Larimer, Douglas, and Weld counties alone. Much of the development being seen in Weld County is in the southern part of the county, and the high development rates in Douglas, Broomfield, and Larimer counties are to be expected as those areas are among the most in demand areas in the state right now for real estate in general.
See here for recent posts about building permits.
New single-family permits during January-April 2013:
El Paso 986
(Note: All permits discussed in this article are single-family permits.)
The largest year-over-year (Jan-Apr 2012 to Jan-Apr 2013) increases in single-family permit activity were found in Broomfield (244 percent), Arapahoe (76 percent), El Paso (61 percent) and Larimer (62 percent.)
See here for full data.