Abstract: Water is considered to be a basic nutrient of living creatures. Without it no one can live. It is not only important for humans but also important for animals and plants. It is used in a number of forms. There are no second words for its importance. It’s a great blessing of God that we are getting water naturally from underground sources. It is also manufactured in industries but in very limited quantity. So water preservation and less contamination is our prime responsibility. But water contamination occurs while drilling a well because of the use of drilling mud. In this paper, some ways of groundwater contamination by drilling mud has been highlighted. The drilling mud is a principle component of oil well drilling and its composition is quite complex as it contains different additives for specific purposes. Entry of mud in the water aquifers is mainly due to the invasion and seepage from the surface storage facilities. So there is need to develop such a mud which will be non reactive with water and also the drilling waste must be disposed in such a way that it will be harmless to the environment and seepage could not occur.