The city of Waukesha, Wis., needs a new water supply. Its longtime aquifer Waukesha has become tainted with several naturally occurring contaminants and is subject to unique geological features that are limiting the water supply. Waukesha is under court order to find a water supply that alleviates these concerns.

After years of research and planning, Waukesha applied to borrow water from Lake Michigan under the Great Lakes Compact, an agreement between the states and Canadian provinces that border the Great Lakes, including Minnesota. The Wisconsin Department of Natural Resources (DNR) has reviewed the application for more than five years, has determined that it meets the criteria under the compact and will forward it to the other Great Lakes states for review and approval.

Minnesota Gov. Mark Dayton will be part of the decisionmaking process. Now that the process is getting underway, it's important that the facts be front and center.

The compact was designed to meet long-term water needs for communities like Waukesha in counties that straddle the Great Lakes Basin. It provides states and provinces with an important tool to meet challenges to public health, regional economies and environmental sustainability. The compact established objective standards and a fact-finding process for the examination of each application, so the outcome would not be subverted by politics and would, in the end, protect the Great Lakes.

Indeed, the choice isn't between protecting the Great Lakes and providing safe drinking water for Waukesha. The compact states clearly that both goals must be met. The compact also creates a fact-finding process to help ensure that the votes by the Great Lakes governors are based on science. That process will begin next year.

Waukesha's application is thorough and is supported by a full environmental-impact study based on a 3,000-page analysis. Waukesha considered 13 other water sources and five other water-supply alternatives to Lake Michigan.

Three different entities (regional planning officials, the city of Waukesha and Wisconsin's DNR) independently found that none of the alternatives proved to be sufficient, cost-effective or environmentally sound.

Waukesha has taken other important steps to deal with its water challenges. It has implemented an aggressive conservation plan to reduce demand and minimize losses to the existing water system. It is already achieving greater savings than projected. The plan includes a daytime ban on sprinkling, a rate structure that incentivizes conservation and public education and outreach. It will achieve 365 million gallons per year of measurable water savings by 2050, or an estimated 10 percent of the total water that would have been used if not for conservation.

But those savings aren't enough. The city still needs a water supply to alleviate health concerns.

Waukesha's plan is environmentally sound and would return all of the water it borrows to Lake Michigan. The total amount withdrawn would equal just one one-millionth of 1 percent of Great Lakes volume, and the same amount would be treated and returned to the lake. There would be no impact on lake levels.

Waukesha is eligible under the compact to make its request, because it is in a straddling county and it sits just 1.5 miles west of the surface water divide for the Great Lakes. Waukesha is one of the very few communities that can apply. It has demonstrated a need for the water and has the ability to treat and return the same amount of water it borrows, both key requirements of the compact.

Some have argued that approving Waukesha's request could set the stage for Great Lakes water being sent far outside the region. That is incorrect. The compact explicitly prohibits water from being pumped beyond counties that straddle the Great Lakes Basin. The purpose of the compact is to protect the Great Lakes, and the Waukesha application guarantees that important objective.

Rejecting an application that complies with all compact requirements would only serve to undermine the validity of the compact. That would be a mistake. The Great Lakes states and the Canadian provinces need the compact to have a say in these important issues and protect the Great Lakes today and into the future.

Shawn Reilly is mayor of Waukesha, Wis.