Pollution

It is hard to find reliable and current data on the level of pollution in Lake Chapala.  Amigos del Lago believes that the water in the lake is being tested regularly, as the lake is a major source of water for Guadalajara. However the results of any such tests are not published.

The water level in the lake varies during the year and there have also been long term variations in the level. The Jalisco state water commission publish the lake levels since 1909 here. Between the early 1980's and 2004 the water level was low, causing higher concentration of contaminants. In 2002, Amigos del Lago presented at the Living Lakes Conference; at that time the pollution was severe due to the historically low water level - click here to see the data.

Since 2004 the water level has risen, diluting the contaminants and reducing the overall pollution. The only reliable data we have available is from Coliform bacteria tests carried out by volunteers and published in March 2008. The results of these tests were very encouraging: 15 of the 16 test sites had bacteria levels well below the Mexican limit. Click here for complete information on the tests. Note that these tests were for e-coli only; this measure is commonly used to determine whether the water is safe for recreational use. Amigos del Lago does not have access to tests for heavy metals or chemicals due to agricultural runoff, and indeed we do not know of any such testing.

The position of Amigos del Lago's on the pollution of Lake Chapala is that the water is safe for recreational use, i.e. swimming and boating. We do not have data on whether fish caught in the lake are safe to eat.