There is no law that says only RVIA certified RVs are allowed in parks, public or private. The RVIA certification can be used as a tool for parks to exclude home built RVs and the like. We have seen some homebuilts that appear neither safe or sanitary. Point out the RVIA requirement in our fine print and we may avoid conflict when we refuse to rent a site.
As for all the other codes, NEC etc. there is no inspector or enforcement agent applying such standards to individuals. You can wire and plumb your rig any way you desire without worrying about being hauled away to electricians or plumbers prison. At least that is how the US works. The systems in Canada and North Korea may be different. Now there may be huge liability issues should someone get injured but that is a different story line.
