HARRISBURG — A constitutional challenge by seven municipalities to Pennsylvania’s new law regulating the growth of natural gas exploration is in the hands of seven Commonwealth Court judges after a hearing Wednesday.

The municipalities want the law overturned; the state wants the case thrown out. The judges also could ask for more evidence before making a final ruling or could strike down only parts of the law. Lawyers said they expect a ruling within several months.

The heart of the argument is the extent of the state’s power to tell municipalities where they must allow drilling-related activity, including rigs, waste pits, pipelines and the compressor and processing stations that help move gas. Among the objectionable provisions cited by the towns’ March 29 lawsuit are requirements that drilling, waste pits and pipelines be allowed in every zoning district, including residential districts, as long as operators observe buffers.

At one point, President Judge Dan Pellegrini asked a lawyer representing the Department of Environmental Protection and the Public Utility Commission what would happen if the state passes similar laws for every industry it considers an economic engine.

“If you make that argument, pretty soon zoning becomes irrational,” Pellegrini said.