In the present investigation, various efficiencies and productivity of N identical partially covered PVT flat plate collectors integrated single slope solar distiller unit have been computed at different water depth under optimized condition to see the effect of variation of water depth on hourly and daily efficiencies and productivity. The meteorological data of 2 months: one belonging to winter season say January and the other belonging to summer season say June have been considered for New Delhi climatic condition. The hourly and daily thermal efficiencies, hourly and daily exergy efficiencies, hourly and daily electrical efficiencies, hourly and daily overall exergy efficiencies and hourly and daily productivities have been evaluated under optimized condition. It has been concluded that the increase in values of average daily efficiencies and productivity is significant till 1.4 m water depth. © 2019 Desalination Publications. All rights reserved.