MOUNT PLEASANT — Businesses could be paying hundreds of dollars more in annual stormwater fees when their bills arrive July 15, town officials said.

A professional office could pay up to $3,200 compared with a current maximum of $1,900, said Hillary Repik stormwater program manager. The fees are computed based on acreage, zoning and the base stormwater fee, she said.

Town Council's Public Services Committee this week raised the annual base stormwater fee from $18 to $30, which is what homeowners will pay. The owner of a vacant lot will pay $15 instead of $9.

Council will consider the higher fees Tuesday. The fee hike is expected to generate $386,000 for the town stormwater management program, Repik said. The state and federal government require the program but don't fund it.

"The town of Mount Pleasant didn't create this," Councilwoman Thomasena Stokes-Marshall said.

The program, which will take about five years to fully implement, will involve water-quality monitoring, the mapping of town drainage, identifying and eliminating pollution sources and public education about reducing stormwater contaminants from sources such as pet waste and yard fertilizer.

Non-compliance can be expensive. Richland County was fined $1 million for stormwater program violations.

Mount Pleasant will identify locations where the stormwater system is being used illegally. An illegal discharge could be a restaurant that dumps cooking grease in a ditch or an auto shop that illegally dumps used motor oil.

Stormwater ordinance violators could face fines of up to $500 per day per violation. The city could shut down a business until the problem is fixed or could bring charges in magistrate's court.

The town's storm drainage system includes 20 miles of ditches, 85 miles of pipe and 6,000 drains that flow to public waters. The EPA has identified stormwater as the nation's greatest threat to water quality. The Wando River, Charleston Harbor, Intracoastal Waterway and Horlbeck Creek are some of the waters that receive town stormwater runoff.

Reach Prentiss Findlay at 937-5711 or pfindlay@postandcourier.com.