In this approach (Fok, 1987), the Darcy-Weisbach coefficient at any point depends on the state of the system at the previous time step. At the outset, the friction coefficient for each pipe is a function of the initial flow, Q₀ , as follows: (i) calculated from the steady-state conditions if |Q₀ | > 0, or (ii) the user-entered value of the coefficient if Q₀ = 0. For the starting value of the friction coefficient, the relative roughness of each pipe is estimated by means of the Swamee and Jain (1976) approximation of the Moody diagram. For subsequent time steps, the Reynolds number is computed at each point on the basis of the previous iteration's velocity and then an updated friction coefficient is ascertained.

The steady-state friction method is actually a special case of the quasi-steady method because it assumes that the friction factor does not vary with time. The quasi-steady friction method is virtually an unsteady method, although one based on steady-state friction factors (c.f. Unsteady or Transient Friction). The quasi-steady method is more computationally demanding than steady-state friction.