Rio on edge due to dirty tap water In downtown Rio de Janeiro, water suppliers are rushing to deliver to customers as the city has been experiencing murky and foul-smelling tap water for one month. On Monday, the Guandu treatment plant which supplies nearly 80 percent of Rio's drinking water was shut down for several hours over suspicions of detergent in the spring. In January, the public water utility attributed the problems to the presence of geosmin, a harmless organic compound. The supply from Guandu had be treated with carbon to get rid of the geosmin. IMAGES AND SOUNDBITES