When a lake’s natural balance is shaken, the waters can be cleaned and restored to health. There are many ways to restore a lake. One of the most effective methods is chemical restoration. A clear case of improvement, Lake Kirkkojärvi in Rymättylä, Finland, was restored in 2002 and 2005 and is according the southwest division of the Finnish Centre for Economic Development, Transport and the Environment, fit for swimming in 2011. The ecological state of the lake has been monitored since the early 1990s, and it has become established on a satisfactory level, while its state before the restoration was poor.