We have night time winter temps that get down in the minus numbers, so I have a quite a bit of anxiety about draining.
Actually, if it's just frost you're worried about, it's not a problem for the sewers. Building codes take this into account (just like snow fall and such).
The main drain will exit the house below the frost line on the front of the house (unless you build on a corner parcel where things can be different) to join the city sewer system. The house will probably be surrounded at the bottom of the foundation by some geotextile covered perforated pipe so the foundation will be kept well drained (it's in the provincial building code).
What is usually the problem in cold environments is water supply pipes that freeze. This always happens when there are pipes running
inside an exterior wall. Insulation is not good enough and the pipe freezes or sometimes bursts. You don't need to install a pipe warming wire (I live in cold Canada and don't have one). If the pipes are inside the house, you won't have any problems.
A well insulated basement is a must if money allowes it. If not, just an insulated exterior wall for the darkroom will be fine (2 if you build it in a corner). It keeps the pipes nice and warm, cuts on dampness, keeps temperatures more consistant and is easier to heat up. A digital thermostat with an electric baseboard are very nice. Dial in the temperature and it stays like that no matter what. When you're using chemicals that have been sitting on a shelf, you barely have to check their temperature (which is room temperature
) I even know a guy who did C-41 without a water bath! In the middle of January, he was going to the darkroom in sandals, shorts and a t-shirt
And since the room is small, it doesn't cost much to heat the few degrees it might be missing. If it gets warm in Summertime, a central Air conditioning vent will be welcome. (But whatever you do, if you install central heating, don't put the furnace
under the bedroom... unless you like sleepless nights...)
A level insulated floor is something I plan for my hopefully up and comming darkroom renovation. I currently have only a concrete floor which has a serious slope (normal, it goes to the basement floor drainage cap). It's hard on the legs, cold for the feet and I can't use an office chair with casters...
I hope it answers a few of your questions... Feel free to ask if you need more information.
