WASHINGTON, D.C. — The $174,000 a year members of Congress get seems like a decent salary. But many, including three members of Hawaii’s delegation, are doing even better. They’re able to supplement their income with thousands more in state pension benefits.

Take Sen. Mazie Hirono. According to financial disclosure records she filed in May, Hirono, after holding several positions in state government, received $46,556 last year from the Employment Retirement System of the State of Hawaii.

Rep. Colleen Hanabusa, who also served in the Legislature, reported receiving $22,158 in Hawaii public pension benefits. Sen. Brian Schatz is also collecting a pension from his time in state government, most recently as lieutenant governor, his spokeswoman said. She did not say how much Schatz is receiving.

Rep. Tulsi Gabbard is not getting a pension benefit, a spokeswoman said. Gabbard served on the Honolulu City Council for about a year, less than the minimum to qualify. She is also giving back five percent of her salary in solidarity with furloughed federal workers.

Members of Congress file disclosure reports each May for their previous year’s earnings. So new members of Hawaii’s delegation, like Schatz, have not yet had to file paperwork disclosing the income they’re receiving this year outside of their congressional pay.

Hawaii’s congressional members are not alone; the National Journal reported this week that about a fifth of Congress is collecting local government pensions on top of their congressional salaries.

Congressional members say they’ve earned the money. And government watchdog groups acknowledge the practice is perfectly legal.

However, the groups also question the appearance of taking tens of thousands of dollars in pension benefits when pensions are falling for their constituents. State workers are seeing their pension benefits lowered to make the retirement system more financially healthy.

“These lawmakers earned their pensions and it is their right to draw them,” said Steve Ellis, vice president of Taxpayers for Common Sense. “But considering the economic challenges facing their constituents, they have to ask if it’s appropriate. Just because something is legal doesn’t necessarily make it appropriate.”

As CNBC reported last year, less than 15 percent of private sector employees in 2010 were enrolled in a defined-benefit pension plan that guarantees paying out a certain amount of money. Instead, enrolled in 401k plans susceptible to the vagaries of the market, many are still reeling from watching their retirement funds wither. Members of Congress, though, have access to the guarantees of a defined-benefit plan.

Not only that, Congress’ pension plan requires less contributions and accrues faster than most private plans. According to a CNBC report, 215 former congressmen and women are receiving an average of $39,576 a year in pension benefits. In comparison, the average amount a private sector worker gets from their pension is about $8,800.

It’s in that context that some question the appearance of drawing thousands from local government pension plans.

“Being a member of Congress is the frosting on the top, while serving elsewhere in government provides the sweet fillings,” said Pete Sepp, executive vice president of the National Taxpayers Union. Taxpayers, he said, “are lucky to have a few slices of bread at retirement.”

Last year, the Employees’ Retirement System of the State of Hawaii — which covers state, county and city employees in the state — was only 59.2 percent funded, said Wes Machida, executive director of the state retirement system. While few state pension systems are fully funded, Hawaii is in the bottom quartile, he said.

The money being drawn by Hawaii’s delegation wouldn’t make a dent in the $8.15 billion deficit facing the state employees plan. But the state, the pension fund’s trustees and public unions agreed to a number of changes to put the fund on course to become fully funded in about 25 or 30 years.

Until then, employees and former employees, including the Congressional members, will not see their annual benefits rise beyond the 2.5 percent cost of living increases they now get.

New and future employees hired on July 1, 2012 or afterward will get less than that. Their pensions will only see cost of living increases of 1.5 percent for at least the next couple of decades. Instead of being able to qualify for pension benefits after five years, they will have to wait 10. Overtime won’t count in calculating the size of pension benefits. And instead of calculating benefits based on the highest three years of salary, it will be calculated on the highest five years, which could reduce the amount they will get.

Dee Okahara, a spokeswoman for the Hawaii Government Employees Association, declined comment on the state pensions being collected by Congress members.

Hawaii’s congressional representatives who are collecting pension benefits have no qualms about it.

“Sen. Hirono served in state government for 22 years as a state legislator and lieutenant governor. Just like Sens. Inouye and Akaka before her, Sen. Hirono receives a pension for her service,” Hirono spokesman Nathan Click said in an email.

Hanabusa spokesman Richard Rapoza also bristled when asked about his boss’ pension.

“Congresswoman Hanabusa earned a state pension as the result of her long and outstanding service to the people of Hawaii in the Hawaii State Senate. She collects a Congressional salary for her continued service to Hawaii in the U.S. House of Representatives,” Rapoza said in an email. “The two are unrelated, except to the extent that her service and experience in the State Senate prepared her to serve effectively in Congress”.

Hanabusa has worked in government to improve retirement benefits for public and private employees, Rapoza said. “The solution to our challenges at both the federal and state levels is to make retirement funding secure, not to question why certain individuals are legally entitled to pension payments.”