hi wagon,

I think you are over reacting to the whole issue as far as agriculture is concerned, don't drink the water from the tank. Just don't use a HDPE tank. As far as the fire protection aspect, you will probable have to provide a pump for delivering water under pressure depending on how high the tank is above your house. Or rely on the fire dept. sucking the water out using their truck pumps and hose trucks. Construction contractors provide a type of system like this when providing water to their construction site. They have 10 foot diameter steel tanks producing about 5 psi pressure and then have large delivery pipes to get the flow rate out of the tank. The tanks are usually 10 feet in the air on a portable trailer frame in order to get tanker trucks underneath the outlet pipe and move them around from site to site. If my calcs are right, for 10,000 gal., you need a tank 10 ft in diameter and 18 feet long. That is a large tank($$) for a small orchard, so I guess the fire protection is paramount. Aloha