I live in Ohio. Temps of -10 F to -20 F are typical. My local zoning code has no restrictions regarding garden ponds. This will not be a swimmig pond. The pond plumbing will be completely separate from the house plumbing. It will contain (decorative) fish and other animals. Most people use the SCH 40 PVC. Some of the plumbing will be burried below the frost line, some below water, and some will be exposed to the weather. Do the codes make any restictions on what can be used for this application? Are there PVC products that can withstand freezing? Something else?