Floating roof storage tank systems and related methods are disclosed. The disclosed systems include a storage tank, a floating roof, and a plurality of acoustic sensors. The storage tank has one or more walls defining an interior space and the floating roof is configured to move vertically within the interior space. The acoustic sensors are levelly mounted along a horizontal plane on the one or more walls of the storage tank. One or more signals received by at least a portion of the plurality of acoustic sensors are used to determine a tilt angle of the floating roof.