"It is my view that adoption of the charter form of government would expand the County's authority to create special taxing districts," the letter states.
Shank, R-Washington, said the letter proves that charter proponents have been "disingenuous."
"They have tried to assert that the charter would not give a county council new taxing authority," said Shank, who opposes the charter. "The letter makes it very clear that that is not the case."
But charter advocates said Friday that Shank is the one misleading the public.
Jeanne F. Singer, former chairwoman of the charter drafting board, said capital projects are by far the most common reason to enact special taxing districts.
"And we already have that ability," Singer said. "That doesn't go away, even if the charter fails. Shank says we're being disingenuous. We think he is using bullying scare tactics."
The issue of special taxing districts has been fiercely debated in the run-up to Tuesday's primary election, when voters will decide whether to adopt the proposed charter.
Residents or businesses in special taxing districts typically pay higher property taxes to fund projects or services in their area, County Attorney John M. Martirano said Friday.
The county commissioners can create those districts now to pay for infrastructure such as roads, sewer and water systems, schools, parks and other capital projects.
Washington County has approved one special taxing district since the state gave it the authority to do so in 1995.
In 1997, the county commissioners approved a special tax on Prime Retail to fund nearly $10 million in infrastructure improvements at its outlet mall near the Sharpsburg Pike/Interstate 70 interchange.
The outlet mall developers requested that tax.
If the charter is approved, special taxing districts could be created to fund municipal services such as fire and rescue programs.
But Singer, who said she has contacted representatives from other charter counties since reading Rowe's letter, said special taxing districts in those counties have paid for capital improvements, not municipal services.
She said that a special taxing district for municipal services could be taken to referendum under the charter.
Under the proposed charter, Washington County's governing body would change from a five-member board of commissioners to a seven-member county council.
The council would be able to pass local legislation, and voters would be able to repeal some laws through referendum, or public vote.
All registered voters, including independents, will be able to vote on the proposed charter during Tuesday's primary election.