TAMPA — If Florida voters say yes to medical marijuana, no one can say yet what role cities like Tampa would have in regulating where it turns up in their communities.

In 21 other states that have legalized marijuana in some form, mostly for medical use, that question has produced a mixed bag of local rules. In Colorado, for example, cities and counties can ban dispensaries, as well as the manufacture and distribution of marijuana.

But that's not likely here, City Attorney Julia Mandell told the City Council on Thursday.

That's because part of the medical marijuana amendment heading for the November ballot is aimed at assuring the availability of medical marijuana in communities, she said.

"I would suggest that there's no way for us to ban that in the city of Tampa in any kind of significant way," she said.

Instead, the Florida Department of Health will shape the regulatory landscape and decide what rules — if any — will be left to local officials, according to Gina Grimes, a Tampa lawyer who has studied the potential impact of the amendment on local governments.

If passed, Florida's proposed constitutional amendment would require the state Department of Health to promulgate rules on medical marijuana by July 2015. (Grimes said the amendment would trump a more restrictive bill the Legislature passed this year allowing the medical use of marijuana with low levels of the active ingredient THC.)

Grimes said the amendment requires the Health Department to adopt procedures for registering treatment centers. But it doesn't say that they do or do not have to address issues of location.

"If they chose to regulate the location of the medical marijuana treatment centers, then you will be pre-empted," Grimes told the council. But she suggested that if the amendment was meant to restrict locations, it probably would have delegated that task to the Health Department.

Thus, she said, there may be more of a chance that issue ends up being addressed at the local level.

If so, the city could have several options, Mandell told the council.

It could seek to regulate medical marijuana treatment centers through its land-use rules, which include zoning.

It could use its business regulations, which are more focused on operations.

Or it could do some combination of both.

Mandell noted that when pain management clinics began to proliferate, some communities enacted moratoriums. But on the recommendation of police, Tampa enacted a business regulation for the clinics so the city knew where they were located.

The city's business regulation gave officials information on clinics' owners, their landlords, their staffs and their facilities. It also made sure they complied with zoning regulations on issues like parking.

And some clinics that couldn't follow the rules had to leave town, she said.

But with so much still evolving about medical marijuana, Mandell said the city will have to follow the issue for a while and take care that any rules it creates treat similar businesses equitably.

"I suspect that if we do this wrong," she said, "we could end up in some significant litigation."