What unit is ETo expressed in? And what time period does the Total Potable Water Allied (gal) refer to? The CI reference guide states that ETo is expressed in millimeters or inches. My research into ETo indicates that ETo is actually expressed in units of volume/time, and that units of mm/day or in/day are common. The form does not provide any guidance on the units for ETo or the TPWA, although the tables are labeled "July" which suggests that the calculation should produce total consumption for the month of July. The translation of the information provided for our building in Tel Aviv does not provide any units - but the calculation appears to be incorrect as the TPWA is 6,003 and the non-potable water used is 408,970.