The basic principles of genetic classification of water regimes are va
lid for irrigated soils, if irrigation rates are taken into account. I
t is proposed that the amount of ground waters involved in the water s
upply to the soil profile be considered at the subtype level. Families
of water regimes are separated by the degree of soil profile moisteni
ng, which is expressed in traditional categories of soil water. The wa
ter supply of soils is assessed according to the reserves of available
water in the 0- to 20-cm (arable) and 0- to 100-cm layers.