Rainwater harvesting is now being popularized as a measure to augment or replenish groundwater supplies, particularly in areas facing the problem of lowering of the water table level. Many techniques of water harvesting are practiced but the following are its four chief types :

(i) Rooftops Rainwater Harvesting : In Tamil Nadu, rooftop rainwater harvesting is compulsory for all households. All building plans must provide for in-built rainwater harvesting systems. Under this scheme, rainwater is to be collected by citizens on rooftops and allowed to be stored in tanks. This water can be mainly used for gardening.

(ii) Check Dams : These are generally natural catchment dams in water deficient areas like Rajasthan, western Uttar Pradesh, Haryana and Punjab. Rainwater is allowed to be collected in natural depressions like the circular tank in Kaza village. Artificial bunds are streams called Kuls are erected to prevent water run-off. Rainwater is used for irrigation and promoting vegetation cover on ground.

(iii) Recharge through hand-pumps : Rainwater is first collected in a reservoir, pond or a tank. Prior planning can also be done to allow rainwater to flow directly into deep wells, particularly those which have dried up. These artificial recharge techniques can be promoted to meet household needs during dry periods.

(iv) Recharge through abandoned well : Abandoned wells are ideal for promoting rainwater harvesting and to replenish groundwater resources to meet the requirements of summer.