This standard covers all the procedures required to determine the field data necessary to calculate a Base Prover Volume (BPV), of either Displacement Provers or Volumetric Tank Provers, by the Waterdraw Method of Calibration. It will enable the user to perform all the activities necessary to prepare the prover, conduct calibration runs, and record all the required data necessary to calculate the base volumes of displacement and tank provers. Evaluation of the results and troubleshooting of many calibration problems are also discussed. Detailed calculation procedures are not included in this standard. For complete details the of calculations applicable to this standard, refer to the latest edition of the API Manual of Petroleum Measurement Standards, Chapter 12, Section 2, Part 4, 'Calculation of Prover Volumes by the Waterdraw Method.'