An investigation by the Chicago News Cooperative found that 40 employees at the Metropolitan Water Reclamation District of Greater Chicago charged about $1 million on the district’s credit cards in the last three-and-a-half years. Most of that money was spent on travel to professional conferences, with employees sometimes staying at such luxury hotels as the Mandalay Bay Resort and Casino in Las Vegas.

At a time when governments across the country have halted nonessential travel by public employees, Richard Lanyon, the executive director of the reclamation district, has attended 14 out-of-town meetings of professional organizations in the last 19 months.

Mr. Lanyon also pulled out his credit card at Gibson’s Bar & Steakhouse, David Burke’s Primehouse and other expensive restaurants to treat employees, lobbyists, politicians and visiting colleagues from similar agencies.

He spent more than $3,400 in September 2009 to charter a tour boat that took 100 guests on an evening cruise on the Chicago River. Officials say the cruise was intended to counter critics who want the district to use what is called “disinfection” technology to treat wastewater before releasing it into the county’s waterways.

The expenditures by district employees are an example of how the relatively obscure agency has remained an island of public employee perks in a time of budget crisis.

In May, the Chicago News Cooperative and the Better Government Association revealed that the ranks of water district employees with six-figure salaries have more than doubled since 2005. At the time, district leaders defended the salaries, saying they were necessary to retain skilled employees and that the agency could afford the high pay because it had done a better job of managing its finances than other local government units had.

Yet Mr. Lanyon recently said the district faced a revenue shortfall of about $24 million in 2011, prompting the agency’s elected commissioners to discuss whether to join other officials who years ago began freezing salaries or imposing unpaid furlough days.

The water agency relies heavily on property-tax revenue, and its board has raised taxes repeatedly in recent years. The owner of a home worth $200,000 pays about $135 a year toward the district’s budget, an increase of almost 30 percent in the past 10 years.

At an Aug. 12 budget meeting of the district board, Mr. Lanyon suggested that eliminating travel could save almost $200,000 next year. The board president, Terrence J. O’Brien, said in an interview last week that efforts to reduce travel costs had already begun.

“Sometimes, things can get repetitive in some conferences,” Mr. O’Brien said. “We’ve asked the board and employees to be more conscious of what conferences they are attending and the number of people who are attending.”

Still, Mr. O’Brien said it was important for personnel to attend seminars to learn about changes in regulations and because people often called to ask for assistance. “We’re pretty known nationally and internationally for our expertise,” he said.

The district sent three employees to the Mandalay Bay for a technology conference in June 2009 and has paid the resort a total of about $7,000 since the beginning of 2007, records show.

Last year, it cost almost $3,500 for an employee to go to a symposium on the Greek island of Naxos, and more than $2,500 was spent to send another official to a three-day conference in Thailand.

“I don’t control where these organizations have their events,” Mr. O’Brien said.

The district paid almost $30,000 to the National Association of Clean Water Agencies for conference registration fees in the past three-and-a-half years.

Mr. Lanyon crossed the country to attend eight meetings sponsored by the association or the Clean Water America Alliance in the past 19 months. He is one of only four people in the country who are on both the 31-member board of the national water agencies’ association and the 34-member board of the alliance.

After the last district board meeting, Mr. Lanyon treated three of the agency’s retirees, who were recently inducted into the N.A.C.W.A. Hall of Fame, and some current employees to lunch at Rosebud on Rush Street before walking back to district headquarters at 100 East Erie Street for another meeting on the agency’s budget crunch.

It was one of many restaurant tabs on Mr. Lanyon’s expense reports, including:

¶$3,289.43 for a pizza party for district employees in McCook.

¶$1,800.05 for a luncheon with dozens of union officials who forged a new labor agreement with the district.

¶$1,635 for a reception in Washington in November 2007. The district treated them to artichoke and goat cheese croquettes, “artisan flat breads” and a $22-per-person open bar for 40 people, according to the district’s contract with the venue, Lounge 201.

¶$576.98 at Gibson’s in Rosemont for six high-ranking district employees and an official of the national water agencies’ association .

Mr. O’Brien and Mr. Lanyon defended using agency money to pay for the meals, describing them as tokens of appreciation for people who had helped the district. Mr. O’Brien, who has been on the board for more than 20 years, said executive directors had bought meals for union leaders after contract talks concluded “as far back as I go at this institution.”

Last year’s 90-minute river cruise on Summer of George cost taxpayers more than $3,400.

Mr. O’Brien said the boat trip helped show local leaders why it could be too expensive to begin disinfecting waste. Critics of the district say disinfection, which is common practice in much of the rest of the country, would result in cleaner waterways.

Asked if he would have hosted the event had he known how bad the district’s financial situation would get, Mr. Lanyon said, “Probably not.”

At the end of an interview in his office earlier this month, Mr. Lanyon said it would be “more fair” to compare the district’s spending to that of private utility companies rather than with other units of local government.

“Of course, gas and electric utilities aren’t subject to the Freedom of Information Act, so you can’t get records of them,” he said. “We would appear paltry in comparison to private utilities if you wanted to compare salaries and expense accounts.”