Approximately 12,000 to 20,000 years ago, the ice dam of the great, frozen Glacial Lake Missoula burst, sending five hundred cubic miles of water rushing over the land. The flood deposited huge boulders and millions of tons of cobble and gravel that, over time, filled the Missoula Valley and created the Missoula Valley Aquifer.

Today the aquifer is the sole source of water for residents in the Missoula Valley. More than 40,000 households depend on it for water every day. Running from Milltown all the way to Frenchtown and up to Lolo, it’s a seemingly endless source of clean, fresh water. Every year rainfall and snowmelt flowing out of the Clark Fork River and local streams seep down through glacial deposits and recharge this vast underground water source. This natural storage tank contains billions of gallons of fresh water but it’s all just below the ground surface – so close that in some places it’s no deeper than 40 feet below the surface.

This closeness makes the aquifer very convenient to get to. But it also makes it very susceptible to contamination. Careless disposal of oil, pesticides or common household chemicals can put dangerous substances into our drinking water. Mountain Water Company’s careful monitoring has kept Missoula’s water safe but we need your help to protect our most valuable resource.

To find out what you can do to protect the Aquifer, click here.

To find out what impact the Milltown Dam will have on the Aquifer, click here.

For more information about how Mountain Water prepares for emergencies and how residents can help by reporting any suspicious activity in and around local water utilities, click here.