- As the father of two college-age kids, Rob Harris, 55, knew that finding money to pay soaring tuition wasn’t going to be easy. Reluctant to saddle himself or his children with loans, the product development manager from Kansas City, Mo., tapped another source: his retirement savings.

Harris plans to pay himself back, but his decision to prioritize his kids’ education is at least partly responsible — along with rising health care costs and a sluggish stock market — for pushing his target retirement age from 59 to 62. “Everyone says you shouldn’t do it, but there were several years the market was a big loss. You’ve got money there, you’ve got a real need, why not use it?” he said.

Harris is among a growing number of Americans who are dipping into their 401(k)s and other defined contribution plans to pay for more immediate needs such as tuition, bills, credit cards and ­mortgages.

One in four American households withdraw a total of more than $70 billion from 401(k)s or similar retirement plans for nonretirement spending needs every year, according to a recent report by the financial advisory firm HelloWallet.

With traditional pensions fading into memory, and Congress considering cuts to Social Security and Medicare, many Americans working in the private sector expect their 401(k) nest eggs to guarantee financial security in their older years.

But in the aftermath of the Great Recession, increased “leakage” from 401(k)s in the form of cash-outs, hardship withdrawals and loans is worrying policymakers and retirement savings experts, who also bemoan the plans’ high fees and stubbornly low ­participation rates.

Some are looking for ways to reform 401(k)s, or even offer innovative alternatives.

One such plan has been proposed by Teresa Ghilarducci, an economics professor at the New School in New York City and an ardent critic of 401(k)s.

“A good pension plan helps people accumulate money, helps them invest money appropriately, and helps people pay out your pension for life, and the 401(k) fails at all three of those dimensions,” ­she said.

Her plan would require that employers deduct 2.5 percent of their workers’ pay, a contribution that businesses could match if they chose. Employee contributions would be ­mandatory.

The money would be set aside in a fund that pays a guaranteed, modest rate of return to supplement Social Security. The return could be guaranteed by a paid fund or an insurance company, and it would be paid out after a worker retired in the form of an annuity for the rest of that person’s life.

Last year, Sen. Tom Harkin, D-Iowa, floated the idea of privately run pension plans he calls USA Retirement Funds. Workers without a pension or a 401(k) would be able to make automatic contributions toward retirement through pretax payroll deductions.

Businesses would be required to contribute as well but would receive tax credits to offset the cost. Workers would receive regular payments throughout ­retirement, like a pension. The proposal hasn’t made much headway.

Whatever politicians ultimately decide, 401(k)s aren’t going anywhere anytime soon, said David John, a senior fellow in retirement security and financial institutions at the conservative Heritage ­Foundation.

“There is always a temptation — and this is especially true in Washington — to completely rewrite the system and specify every detail of it, but the fact is that although the 401(k) system is imperfect in many ways, it’s a vibrant, active system,” he said.

A government-specified program, he added, wouldn’t have the same vibrancy and would be tough to pass against industry opposition. Instead, policymakers can take smaller steps to improve the individual retirement account/401(k) system, John said.

To discourage people from tapping their savings, policymakers could make it easier for old 401(k) balances to be automatically transferred to a person’s new employer. This would reduce cash-outs when people change jobs.

For now, though, 401(k)s remain “as good a place as any” to save, as long as investors don’t treat the plans as rainy day funds, he said.

Their success depends on long-term investment.

“Keep saving, save throughout your career, and don’t touch the money,” John advised.