Maui County’s years-long legal battle over its Lahaina sewage treatment plant have come to a merciful end. Now the real work begins.

For decades, the county used injection wells at the plant to pump millions of gallons of treated sewage daily into the groundwater near Kahekili Beach. That nutrient-laden effluent — pollution, really — ended up in Maui’s nearshore ocean waters, about half a mile away.

This is obviously a bad idea. The damage caused to the reefs and marine life prompted a 2012 lawsuit by environmental groups, triggering litigation that cost Maui County about $5 million in futile attempts to keep doing what it was doing — a legal journey that led to the U.S. Supreme Court and a major victory for environmentalists.

The high court, in a 6-3 ruling, found that the Clean Water Act (CWA) requires a permit when “there is a direct discharge from a point source into navigable waters or when there is the functional equivalent of a direct discharge” — in this case, a discharge into groundwater that reaches the ocean, under certain conditions. The decision essentially affirmed several lower court rulings that reached similar conclusions about the reach of the CWA.

The bottom line: In order to keep using the injection wells, Maui County will be required to obtain a National Pollutant Discharge Elimination System (NPDES) permit.

Now the dust has settled, the landscape has changed significantly, and the way forward is clearer.

Thankfully, Maui County has decided to look forward, not back. Last month it announced that it would work to comply with court decisions and a 2015 settlement agreement reached by the litigating parties.

The settlement means the county will invest in projects that would recycle the wastewater to irrigate the dry upper slopes of West Maui. It’s hoped that the county will end its use of injection wells altogether.

“In Lahaina, the Department of Environmental Management is rehabilitating upper-elevation reservoirs so that the water can be pumped and stored there for use on the slopes,” the county said in a press release. “This can provide water for irrigation as well as establish greenbelts for fire protection.”

The cost of this effort could reach $2.5 million or more. But it’s the wiser option.

Modernizing our public infrastructure to handle waste sustainably is a long-term investment with permanent benefits — a much cleaner environment, from our homes to the beach, for generations to come.