Chicago Mayor Rahm Emanuel is seeking higher utility taxes to keep the city’s largest pension fund from running out of money and set all four retirement plans on a path to solvency.

The city wants to raise the levies on water and sewer bills to shore up the Municipal Employees’ Annuity and Benefit Fund of Chicago, the most underfunded of the four pensions, and Emanuel plans to discuss the plan Wednesday at an investor conference in Chicago, according to a person familiar with the plan who declined to be named before the mayor’s announcement. Without changes, the pension that serves more than 70,000 workers and retirees is on track to run out of money within a decade.

For years, Chicago failed to put aside enough taxpayer money to cover the rising cost of pensions. Its four retirement funds are short by $34 billion, and the strain is pressuring the budget as officials are forced to catch up. The stress spurred Moody’s Investors Service to slash Chicago’s rating to junk in May 2015, making it the lowest-ranked major U.S. city except once-bankrupt Detroit. On average, all four of the city’s pensions are only 23 percent funded, according to an annual financial analysis.

Emanuel’s administration has taken steps to reverse the liabilities it inherited. In October, he pushed through a record property tax hike to shore up police and fire pensions. In May, he reached an agreement with unions to save the laborers’ fund from insolvency. That accord still needs state approval. Even with these steps that inflict pain on taxpayers, it will take decades to bring pension assets in line with promised benefits.

While these are positive steps, the unfunded liabilities aren’t going away. They’re just getting worse at a slower pace, Moody’s said in a July report. Chicago would have to raise nearly $1 billion a year to see a drop in pension liabilities. And that’s in addition to the $543 million property tax jump already approved for the public-safety funds.