Help on building a well house?

Moved into a new house and the small well house is in dire need of replacement, can anyone guide me in the right direction to plan my new well house? The concrete pad is about 5feet by seven feet and the existing house is about the size of a large dog house. I live in Southern Illinois and the winters have been fairly mild, the only heat source is a clamp work light housing with a hundred watt bulb and seems to keep it from freezing, so the last owner says, but I would like to use heat tape and maybe a thermostat in the new design. Thanks for you help in advance!....Darren.

I had a small pump house that looked like a wishing well when I moved in. Very tacky and falling apart. I checked with the local building official, and found I could build anything under 100 sq ft without a permit, so that set the basic design. I went with an 8x12 shed on a 4" slab, with a hip roof, shingles to match the house, a couple of windows and a 4' door. Cost me just under $1000, I guess. Heating is not a problem here . There's enough room for the water treatment system, lawn equipment, space for a workbench, etc.

You might try this:
http://www.public.iastate.edu/~mwps_dis/mwps_web/plans/74001.pdf

DSK