The picture is mixed for ground water as well. Two-thirds of Minnesotans draw their drinking water from underground, and we're using more of it all the time. For example, irrigation doubled from 1986 to 1996. Although ground water may seem safely beyond harm, it's vulnerable to what happens on the land surface. We know that nitrates are too high in ground water under some parts of Minnesota.
Lakes are a cornerstone of the good life in Minnesota.
But they face an uncertain future. Rapid development of shorelands, exotic species, and water pollution threaten them. Phosphorus and nitrogen, washed into lakes from roads, fields, yards and septic systems, act as fertilizer for algae and weeds, turning the water green and soupy. Airborne mercury from factories, power plants and incinerators falls into our lakes. There it can build up in fish tissues, causing the state to issue advisories on how much fish anglers can safely eat from certain lakes.