The bottom of a ground-level or buried drinking water storage tank shall be located at least 3 feet above the 100-year flood level or the highest known maximum flood elevation, whichever is higher.
When the bottom of a drinking water storage tank will be placed below the normal ground surface, it shall be placed above the local ground water table.
When the roof of a drinking water storage tank will be covered by earth, the roof shall be sloped to drain toward the outside edge of the tank.
Utah Admin. Code R309-545-8