RICHMOND — A group trying to loosen Dominion Energy’s perceived grip on Richmond is offering to donate up to $20,000 to legislators who promise to swear off campaign contributions from the power giant.

The offer from Clean Virginia — sent to all 140 legislators on their state email accounts on May 18 — raised concerns among some senators and delegates, who said they fear that it constitutes a textbook quid pro quo.

Even some who were inclined to accept the offer say they are checking with lawyers first.

“I’m fully supportive of what they’re trying to accomplish, but they may have stepped on a land mine on the way to getting there,” said Del. Lee Carter (D-Manassas).

Clean Virginia, a spinoff from a political action committee headed by former Democratic gubernatorial contender Tom Perriello, stood by its offer, although it tweaked the terms somewhat last week. Executive Director Brennan Gilmore said the group had vetted the proposition with lawyers, who concluded it was legal because it would reward legislators who change the way they campaign, not the way they vote.

“We understand the challenges of funding campaign efforts and want to ensure that funding is available to replace the huge sums that these utilities have given to politicians throughout Virginia,” Gilmore said in the May 18 email to legislators.

It asked them to sign a pledge to take no money or gifts from Dominion, the smaller Appalachian Power Co. or from their PACs, lobbyists or executives. They would also would have to promise to divest from any personal stocks or investments in those companies.

The email offered $2,500 per year to delegates and $5,000 per year to senators.

“We are not telling anyone how to vote or what to do in their capacity as a lawmaker,” said Clean Virginia Chairman Michael Bills, a Charlottesville investor and co-founder of the Sorensen Institute for Political Leadership, which educates future political leaders on ethics in government. “Lawmakers are free to vote and do as they wish, and . . . that’s what they should do. We simply want to end the cycle of corruption endemic in Virginia state politics.”

Clean Virginia began as a good-government and environmental project of New Virginia Way, a PAC that Perriello launched to support progressive candidates after losing the Democratic nomination to now-Gov. Ralph Northam.

Perriello is not directly involved in the effort but said he is “still very supportive of the group and the cause,” including the proposed pledge, which he said is “shaking things up with the usual suspects.”

Gilmore said last week that “a number” of lawmakers had accepted the offer and that the group is “in conversation” with others. He declined to be more specific.

In a statement late Friday, the group said that instead of asking legislators to sign a pledge in exchange for donations, it would look for public statements or other evidence that the candidate had sworn off Dominion funds.

“It is both revelatory and absurd that the notion of refusing to accept money from regulated utilities is unethical, but that accepting tens of thousands of dollars from these utilities to do their bidding in the General Assembly is commonplace,” Gilmore said.

Del. Sam Rasoul (D-Roanoke), who took the pledge before Friday, said many interest groups base donations on how candidates fill out questionnaires about specific policy questions.

“This is maybe even one step back from that,” Rasoul said. “This is not about voting for or rejecting a Dominion bill. I really don’t buy the quid pro quo argument.”

Stephen Spaulding, chief of strategy for the good-government watchdog Common Cause, said he was “sympathetic” to Clean Virginia’s “overall policy goals” but found the emailed offer “problematic” — particularly because it was sent to official state email accounts, which should not be used for campaign purposes.

“It’s a bold approach — maybe just a little too bold,” said Del. Marcus B. Simon (D-Fairfax).

Del. Lamont Bagby (D-Richmond) called the effort “very well intended” but “just a bad way of going about it.”

Dominion spokesman David Botkins declined to comment.

Dominion is the state’s largest corporate political donor, giving about $10 million to Virginia candidates in both parties over the past decade. Critics say that has enabled the company to win sweetheart deals in Richmond — a notion the company and many legislators dispute.

Scrutiny of the company has grown recently among populist legislators, particularly as Dominion began pursuing one of two natural gas pipelines planned to cross through some of the states’s most scenic corners.

A handful of legislators from both parties proposed bills this year to ban political donations from Dominion and any other state-regulated monopolies, but the legislation went nowhere.

Sen. David R. Suetterlein (R-Roanoke), who along with Sen. J. Chapman “Chap” Petersen (D-Fairfax City) and Del. R. Lee Ware (R-Powhatan), is among Dominion’s sharpest critics, suggested that Clean Virginia look at the voting records of legislators who share their goals and give accordingly.

“If someone’s concerned about the ratepayer, and they like what Chap Petersen, Lee Ware and I are trying to do, they ought to just support us,” Suetterlein said.