The lower Indus plain, which is known as Sindh, is desert, hot and arid. The maximum temperature ranges here from 95o F in the south to 121o F in the north. The average annual rainfall, which all comes in summer, is less then 10 inches and decrease from an annual total 8 inches in the south to 3 inches in north. The Indus enters Sindh near Kashmore, at about 200 ft above sea level. From Kashmore to the Arabian Sea the plain extends over an area of about 248,000 sq miles, and has a mean south gradient of 6 inches per mile. The Indus is the main river carrying the major surface flow. It draws its water from melt and permanent glaciers from the mountains in the north east at Kailua’s in Himalayas. Agriculture here has always been completely dependent on irrigation. This part of the subcontinent was the first region to reclaim for farming but the works of water control system constructed at that time were abundant more than 3000 years ago, and were not restored on a comparable scale until late in the last century. Many developments were carried out here, depending upon the current knowledge of the experts of that era. Only a few records have been preserved to indicate the ancient irrigation systems practiced in Sindh. The records reveal the presence of the canals before the Moen-Jo-Daro civilization, but the condition of canals was very poor; they were unlined and awkward in shape. Agriculture advance has accelerated in the last century through the construction of Barrages and lined canals and, recently through high dams in upper valley section and through tube wells in lower Indus valley. Our concern is with the last of these innovations, the tube wells, and more widely with the importance of ground water in the modern economy of Sindh. The exploration and tapping of aquifers have effected revolutionary changes in the rural economy of Sindh, not least in the struggles against the disastrous process of salinity of surface soil, the most unfortunate side-effect of large scale canal irrigation. We observe, however, that the discovery and mapping of groundwater deposits requires special techniques, huge capital and local experience. We further observe that the use of groundwater varies greatly from one district of Sindh to another. In order to discover why this is so, we chose 6 contrasting administrative units or dehs, three to the West of the Indus – Allahabad, Pat and Mehar served by Dadu canal, and three to the east called Manahi, Bundh and Tando Adam served by the Rohri Canal. The first three of these have few tube wells and make little use of groundwater, while the second group has many working tube wells and bring, to the surface much deeper subterranean water. After a close study of the lay-out, economic, sociology, and tenure systems of the six villages, we conclude that the last of these factors the type of land holding is mostly accountable for the observed differences in the use of groundwater. We conclude that tube wells are too expensive for the ordinary small-holder, and that they are of benefit mainly for the large landowners who can afford them. In due course, as the land reforms are more widely effective, the situation may change. Meanwhile, it is evident that there is still much scope for the further exploitation of groundwater which, together with other technological changes, has gone far towards making life more secure, for the large landowners than the small farmers.