California - Health

Moisture

The house has the builder's standard water control and nothing more: there is a polyethylene sheet under the slab, but no gravel.  The windows have sill pans and are have are wrapped with typical peel-n-stick material, and the whole thing is then wrapped in double layer of heavy building paper. We did create fairly large overhangs (most of them are 24"), which helps keep rainwater off.  In addition the west porch shields most of the west side of the house from driving rain, which occurs frequently.

While the site isn't really a dry climate, it is bone dry for much of the year, so the standard

Paints, Finishes, Glues and Caulks

Because California has strict VOC limits, all the paints, finishes, glues and caulks sold in the state are theoretically low VOC. This doesn't means that they're particularly low VOC, just that they meet the state standard.  It also doesn't mean they're non-toxic.  We used only mainstream products everywhere.  The one place where we could have obviously reduced VOC, we chose durability instead: we used mostly oil based clear finishes rather than water based polyurethane.  The exception was on cabinet shelving, windowsill and the oak flooring, where we used water based polyurethane.  To compensate, we aired the house our constantly.

Random Toxics

We used the standard pressure treated lumber for all the sill plates, but otherwise used not pressure treated lumber.  All the outdoor supply lines are PVC, largely because there is no real alternative (due to the volume requirement for fire sprinklers, the supply lines are all 2" and the main line from the tank is 4" because it feed a hydrant).