Sites suitable for parks, schools, playgrounds or other public usage, as required by the City, should be carefully considered in collaboration with the P&Z and so indicated upon the Preliminary Plat. This is done so that these sites can be checked for conformity with the recommended locations indicated in the Comprehensive Plan and so that these sites should be in conformity with the general requirements of the City and in keeping with modern planning principles. They shall be of adequate size as recommended by the P&Z and as may be required by the City under its policies and specifications. The P&Z may require the owner or subdivider to obtain a letter from the appropriate independent school district stating that provisions for the site of future schools, if such be required, are adequate. If a school site is not required, the letter is to so state.