A method and system for treating golf course sand bunkers to maintain sand in a playable condition by improving the propensity for water to pass through, opening clogged drains, and decomposing organic sediment. The method and system include a drainage solution and a microbe-based solution which are applied to the sand bunker in at least two applications, separated by a period of time, preferably a month. The drainage solution comprises a blend of surfactants and/or physical stability agents and the microbe-based solution comprises a liquid and microbes.