Re: pipe materials
There were -- and still are -- legitimate health concerns with earlier types of plastic pipe. Polybutylene, black polyethylene, and PVC all have the potential to leach chemical into the water supply, especially if used with hot water. (PVC and black polyethylene are generally not suitable for hot water anyway, due to the fact that they are unable to withstand high pressure at high temperatures.) CPVC leaches much less than these other materials, but it still can leach. Cross-linked polyethylene (PEX), by comparison, is extremely stable and has not been shown to leach harmful amounts of chemicals even when used with hot water.
Some people still insist that plastic is not healthy and that you should only use copper. They don't trust PEX, even though it has been proven to me much safer than the other plastics -- I believe this is due to a general bias against plastics.
Copper, though, is not perfectly healthy and is not immune to leaching. Given the right water conditions, it, too can leach into the water. The problem with copper is rather than leaching pure copper, it reacts with other things in the water to form potentially harmful copper compounds.
Galvanized steel is probably even safer than copper, since few iron compounds are harmful to your health and may even be beneficial. However, iron is fairly reactive, so it can corrode quickly. It "typically" lasts between 5 and 50 years, depending on the composition of your water. Besides, steel is expensive now and installation is labor intensive. For these reasons it's generally not used in new construction anymore.
So there's no product that's entirely free from potential harmful effects to your health, but I believe that PEX is the safest from a health perspective.
Every plastic should be protected from ultraviolet light. When used outdoors, it should not be directly exposed to sunlight. Ultraviolet light is a catalyst that accelerates oxidation of the hydrocarbons in the plastic.
The "Senior Member" designation under my name doesn't mean I know a lot, it just means I talk a lot.I've been a DIYer since I was 12 (thanks, Dad!). I have read several books on various home improvement topics. I do not have any current code books I can refer to. I was an apprentice plumber for two years.