Maintaining stability of public facilities, especially public roads, is very necessary, so the stabilization efforts must be carried out. The water from seepage that comes out of sandstone layer carries material with fine particles and this causes the rock cohesion to decrease and thus leading to scouring. As a result of the scouring, the layer becomes overstep and can disturb road stability. This study was conducted to provide simple but measurable recommendation for maintaining road stability after the previous stabilization effort failed. The method used a fluid mechanics approach in which water from the formation was given space to come out of the formation without carrying fine particles (cement). The analysis was carried out using the finite element method by installing horizontal drain pipe. The result of analysis shows that the horizontal drain installation helps water to come out without creating an overstep layer. The recommended horizontal drain is 8 m long with a slope of at least 3% and a length of 1 m that must enter the sandstone formation as a water source. With this method, the road stability can be maintained and the stabilization can be carried out in an easy, inexpensive, and applicable way.