Repairs, reconstruction, replacement, or improvements to existing farmhouse structures located in designated floodways and which are located on lands designated as agricultural lands of long-term commercial significance under RCW 36.70A.170 shall be permitted subject to the following:

(1) The new farmhouse is a replacement for an existing farmhouse on the same farm site;

(2) There is no potential safe building site for a replacement farmhouse on the same farm site outside the designated floodway or the location requires close proximity to other structures in the farm operation in order to maintain the integrity and operational viability of the farm; in no case shall a replacement be located into an area with higher flood hazards in terms of depths, velocities and erosion;

(3) Repairs, reconstruction, or improvements to a farmhouse shall not increase the total square footage of encroachment of the existing farmhouse;

(4) A replacement farmhouse shall not exceed the total square footage of encroachment of the structure it is replacing;

(5) A farmhouse being replaced shall be removed, in its entirety, including foundation, from the floodway within ninety days after occupancy of a new farmhouse;

(6) For substantial improvements, and replacement farmhouses, the elevation of the lowest floor of the improvement and farmhouse respectively, including basement, is a minimum one foot higher than the base flood elevation;

(7) New and replacement water supply systems are designed to eliminate or minimize infiltration of flood waters into the system;

(8) New and replacement sanitary sewerage systems are designed and located to eliminate or minimize infiltration of flood water into the system and discharge from the system into the flood waters; and

(9) All other utilities and connections to public utilities are designed, constructed, and located to eliminate or minimize flood damage.