Is it a California law that a pool has to be pre-plumbed for solar heat and if so would it automatically be included in the price?

To the best of my knowledge (and several other good sources), there is NO law in California that a pool must be pre-plumbed for solar heating. However, local building codes and common building practices may vary. I would simply call your local city or county building department and check the building codes for your local area. Pre-Plumbing for solar heating may or may not be included in the price. Check with your contractor or installer to find out if it is included. Here is another good link to review: http://www.sdenergy.org/ContentPage.asp?ContentID=134&SectionID=120&SectionTarget=44 That being said, it may be a VERY good idea to pre-plumb your pool for solar heating. Solar heat has many great advantages and continues to gain popularity for Pool Heating, especially in sunny California. Hope this helps ... Yes - the system much be plumbed such that there is sufficient space/clearance to add the valves and pipes to roof for a future solar install. No added cost - law is just to make sure the physical layout of the original pipes allows for the addition of solar in the future.