The state of the practice in surface hydraulic conductivity (Kfs) measurement is well developed. Laboratory test are conducted in sites where undisturbed sampling is possible; whenever this is not possible, field methods, known as "constant head methods", produce acceptable results. However, in granular soils with high fine content, methods such as Haefeli and Matsuo are either costly or inaccurate. This paper presents an approach to conduct field tests as "falling head" tests, and the results are compared with two generally accepted methods. The computed values for Kfs are always higher than laboratory values, which can be explained by the lack of a clear wet front in silty sands.