WASHINGTON — After weeks of Hillary Clinton pounding him as weak on gun control and health care, Sen. Bernie Sanders shot back with a personal attack Sunday night in a feisty fourth Democratic debate.

The Vermont senator accused Clinton of being unwilling to take on Wall Street because she takes finance-industry money.

“I don’t take money from big banks,” Sanders said. “I don’t get personal speaking fees from Goldman Sachs.”

Sanders continued to pounce at the Charleston, SC, forum hosted by NBC and YouTube.

“Secretary Clinton — and you’re not the only one, so I don’t mean to just point the finger at you — you’ve received over $600,000 in speaking fees from Goldman Sachs in one year,” Sanders said.

“I find it very strange that a major financial institution that pays $5 billion in fines for breaking the law, not one of their executives is prosecuted, while kids who smoke marijuana get a jail sentence.”

Clinton insisted she’s tough on Wall Street.

“There’s no daylight on the basic premise that there should be no bank too big to fail and no individual too powerful to jail,” Clinton said. “We agree on that.

“But where we disagree is the comments that Senator Sanders has made that don’t just affect me, I can take that, but he’s criticized President Obama for taking donations from Wall Street, and President Obama has led our country out of the great recession.”

Clinton touted her experience and know-how to make practical reforms without blowing up the whole system, such as improving ObamaCare and making college debt-free rather than tuition-free.