Rainwater harvesting can ensure an independent water supply during water restrictions, though somewhat dependent on end-use and maintenance, is usually of acceptable quality for household needs and renewable at acceptable volumes, despite climate change forecast.It produces beneficial effects by reducing peak storm water runoff and processing costs. In municipalities with systems, reducing storm runoff is especially important, because excess runoff during heavy storms leads to the discharge of raw sewage when treatment plant capacity cannot handle the combined flow. Rainwater harvesting systems are simple to install and operate. Running costs are negligible, and they provide water at the point of consumption. Rainwater harvesting in urban communities has been made possible by various companies. Their tanks provide an attractive yet effective solution to rainwater catchment. Sometimes a practice is adopted of directing collected rainwater deep inside the ground through pipes or shafts. Such a practice will carry surface pollutants to the ground water and thus pollute it. The best practice is to store water in ponds, lakes and other unlined surface reservoirs so that the water gets filtered through before entering the ground.