Humans have always been exposed throughout its period of existence to naturally occurring sources of ionizing radiation or natural background radiation. It is an established fact that even these low background doses are harmful to man and cause increased cancer risk. About half of our radiation comes from radon, a radioactive gas coming from normal materials in the ground. Several building materials such as granite, bricks sand, cement etc., contain uranium in various amounts. The radioactive gas 222 Rn produced in these materials due to decay of 226Ra is transported to indoor air through diffusion and convective flow. It seeps out of soil and rocks, well water, building materials and other sources at a varied rate. Amongst the naturally occurring radioisotopes, radon is the most harmful one that can be a cause of lung cancer. Radon isotopes are born by the decay of radium, and radium production in turns comes from uranium or thorium decay. For humans, the greatest importance among Radon isotopes is attributed to 222 Rn because it is the longest lived of the three naturally produced isotopes. [1]Drinking water also poses a threat. Radon gas is dissolved in water and is released into the air via water faucets, showerheads, etc. the lack of understanding has so far lead to speculative estimates of pollutant related health hazards.