Impact localization in a floor is complicated due to the dispersion-caused distortion of the generated floor waves. Current localization methods that try to overcome the dispersion problem are computationally expensive, taking in some cases 2 seconds to yield a single footstep location estimate. If an accelerometer sensor network is utilized to localize footsteps, and consequently track an occupant's path, then there is a need for computationally fast algorithms that are able to keep up with the walking (or running) impact frequency; therefore, in this paper, a practical algorithm is proposed for footstep impact localization in an instrumented floor. The proposed algorithm has promising sub-meter localization accuracy and is computationally fast. In addition, the algorithm does not require estimation of floor-dependent parameters, which is an additional advantage since estimating floor-dependent parameters in a floor will have relatively high uncertainty as the floor cannot be treated as an isotropic/homogeneous material. The proposed algorithm is evaluated using simulations and an experiment in an operational smart building.