Major Causes of Contamination: Untreated Sewage

Raw sewage flowing into Lake Atitlan

Thousands of gallons of sewage flow into the lake every day

There are not enough wastewater treatment plants around Lake Atitlán to treat the ever increasing amount of raw sewage produced by the area's growing population. Most of the existing plants operate well below full capacity. They simply remove solids and do little to reduce the volume of pathogenic bacteria entering the lake. Only one of many planned new facilities has been built so far, and municipal authorities do not have the resources they need for maintenance and upgrading.

As a result, thousands of metric tons of raw sewage or improperly treated wastewater from households and businesses in more than 20 towns enter the lake each year. The ecosystem is under constant siege from putrefactive bacteria and other pathogens. At the San Bartolo wastewater treatment plant in Sololá, the outflow contains over 1,000 times the accepted level of coliforms (such as e-coli). This water is actually used for direct irrigation onto vegetable crops.