Decentralisation is one of the best ways to ensure energy and water security . As far as water is concerned , harvesting rainwater and reusing grey and black water after necessary treatment can completely meet the household requirement . One of the other ways to ensure water security is by making full use of the shallow Aquifer . water present in soil pores at shallow depths at atmospheric pressure is called a shallow Aquifer or an unconfined aquifer . The rainwater from the roof and other surfaces can be pushed into the soil through a recharge well which saturates the soil . A withdrawal well can be made at a suitable distance , which can be used for extracting the water from the soil pores.