First things first since you said you want it up to snuff.
Iowa like most states uses NFPA 395, Standard for the Storage of Flammable and Combustible Liquids at Farms and Isolated Sites
To meet this requirement you need to move the tank.
The tank needs to be moved so it is located outside and at least 40 ft. from any buildings, haystacks, grain bins, or other combustible structures.
The tank shall also be located so that any vehicle, equipment, or container that is being filled from the tank is at least 40 ft. from any combustible structures.
If you can not move it to a isolated spot; or you want to hook something permeate to it such as a irrigation motor you can put it closer to a building but you need to follow the more stringent rules of NFPA30; NFPA30A; and NFPA37.