Lake Horowhenua is a small, shallow lake located near Levin, New Zealand. Between 1952 and 1987, the city of Levin dumped untreated sewage into the lake, polluting it severely. As a result, Lake Horowhenua is now considered one of the most polluted lakes in New Zealand, and its water poses health risks to small children and dogs. In recent years, the Lake Horowhenua Trust has worked to restore the lake's wetland ecosystem by planting trees around the shoreline. However, the lake still contains low levels of fish and pollution.