Other methods, such as basing an estimate on the water availability, are even more unreliable. See J. Wilkinson, Ancient Jerusalem, Its Water Supply and Population, Palestine Exploration Quarterly 106 (1974), pp. 3351. I cannot accept some of the authors conclusions because they are based on assumptions which cannot be proven or disproven; for example, his assumption that an aqueduct led water to the city from Ein Etam during the First Commonwealth, or the arbitrary consumption figure of 20 liters per person per day. Nevertheless, Wilkinsons study is a valuable one.