The equation used to describe steady-state water flow through a soil in response to hydraulic pressure (or suction in unsaturated soil), osmotic pressure, and temperature gradients is J_v = L_vv grad P + L_vD grad ? - L_vq grad T. Published research results indicate that L_vq is relatively independent of suction when suctions are greater than about 0.06 bar, becomes quite small when suctions are lower than 0.06 bar, and increases in a predictable manner as the average temperature increases. A value of 3.0 × 10^-3 cm²deg^-1hr^-1 is suggested for L_vq for estimates of water flow in response to temperature gradients. L_vD can be considered to be zero for suctions less than about 0.25 bar except under conditions of very high clay content. The value of L_vD is not likely to be greater than 10 per cent of L_vv (3 per cent is suggested for approximate calculations) at suctions between 0.25 and 1 bar. L_vD would more nearly equal L_vv at greater suctions, but no data are available on this relationship at higher suctions. The suggested values of L_vq and L_vD are based on relatively few data and are to be considered as approximate. Additional data are required for more specific values for these coefficients.