We depend on an adequate supply of clean water for our daily life/ our food supply and many industrial processes. Regular rains recharge groundwater levels when rainwater is captured and not lost as runoff into rivers, lakes or the ocean. Turfgrass traps and holds much excess surface water 'from storm runoff. As a result, more water filters down through the turfgrass and into the soil. This clean, filtered water then enters the groundwater system. Water that does run off to enter lakes and streams moves more slowly through established turfgrass areas and enters lakes and rivers with less sediment.

Turfgrass absorbs and filters rainwater and surface water in the following ways:

Turfgrass traps and filters water better than agricultural crops. For example/ in one research project, turfgrass was compared to a conventionally-grown row crop. The row crop lost an average of 0.65 inch of surface water runoff per acre per month during the growing season (May-September). Surface water runoff from turf grass was less than one-tenth that amount. Less surface water runoff means less loss of nitrogen and phosphorus. The amount of nitrogen lost from turfgrass in the above study was 100 times less than the amount lost from the crop plots.

The ability of turfgrass to absorb and filter rainwater and surface water produces several important benefits. First, more water is retained from rainfall and does not escape as surface water into streams/ rivers and oceans. Second, this water is filtered through the turfgrass and soil before it enters the groundwater. Finally/ because turfgrass loses almost no water in most storms/ losses of nitrogen and phosphorus are nil compared to farmland.

Thus, turfgrass can reduce the risk of groundwater contamination. In fact, one study suggested that turfgrass reduces water runoff to a point where it may lessen the need for expensive storm management structures in urban tract developments.

Turfgrass filters so well that many golf courses today are using effluent (waste or recycled) water for irrigation. This not only reduces the total amount of drinking water needed for irrigation; it also effectively filters waste water before returning it to the groundwater.