All measurements, tests and analyses of the characteristics of waters and wastes to which reference is made in this chapter shall be determined in accordance with the latest edition of "Standard Methods for the Examination of Water and Wastewater," published by the American Public Health Association, and shall be determined at the sampling station  provided, or upon suitable samples taken at the sampling station.  In the event that no special sampling station has been required, the sampling station shall be considered to be the nearest downstream manhole in the sewer from the  point at which the building sewer is connected.  Sampling shall be carried out by customarily accepted methods to reflect the effect of constituents upon the sewage works and to determine the existence of hazards to life, limb and property.  (The particular analysis involved will determine whether a twenty-four hour composite of all outfalls of a premises is appropriate or whether a grab sample or samples should be taken.  Normally, but not always, BOD and suspended solids analyses are obtained from twenty-four-hour composites of all outfalls whereas pH's are determined from periodic grab samples.)  (Ord. S-39108, 1979).