The Dukes County commissioners found themselves on the defensive last week when about a dozen residents crowded a public hearing to voice their discontent with existing and proposed rules for Joseph A. Sylvia State Beach.

The commissioners had said they wanted to strike a balance between preserving the beach and protecting its nesting birds while also allowing public access.

Also, due to an increase in requests to use the public beach for large private functions, the commissioners sought to update the beach rules so as to discourage such events.

But people attending the hearing criticized the commission’s efforts as costly overregulation that would inadvertently discourage the traditional smaller gatherings that the commissioners were trying to preserve.

After debating among themselves about specifics such as what constitutes an event, the commissioners voted to send the proposed rules back to a subcommittee for reconsideration.

State Beach, an ocean beach that spans Oak Bluffs and Edgartown along the northern edge of Sengekontacket Pond, is one of the most popular and well-used public beaches on the Vineyard.

Members of the commission spent the past year working with various conservation groups and government entities on the Island to update the rules concerning the beach.

Some rules were simple. Residents attending the hearing did not take issue with them, quietly accepting proposed prohibitions of dogs and kite surfing on the beach during the nesting season.

But when the topic turned to beach events, residents spoke out.

“What we’re really trying to do is discourage big events,” commission chairman Leslie Leland said after the meeting.

But many at the meeting were upset that a group of as few as 20 people gathering on the beach would constitute an event and thus require a $100 permit (up from $50), a $100 cleaning deposit and a handicapped-accessible portable toilet at the event organizer’s expense.

“Twenty people is a good-sized family and a lot of good-sized families come out here for the summer,” said Tim Connelly, a resident of Edgartown. He and others suggested that the defining number for an event be increased to 40.

Even though the proposed changes decreased the required number of portable toilets for parties of 20 to 40 people from two to one, Mr. Connelly and others were discontent with any requirement of something so expensive to rent.

“Why require Porta Potties for 20 people when the thousands of people who use the beach during the day go without them?” Mr. Connelly asked.

The proposed rules also affect businesses. Event organizers like the public beach because it’s cheaper than other venues. But a commercial activity, which the commission defines as “any activity or event where the applicant or its designees receives money in anyway related to the use of the beach,” must adhere to stricter and more costly regulations.

Fella Cecilio, who runs Fella Catering, spoke at the meeting against the proposed rules.

As a commercial service provider, Mr. Cecilio said, he would have to spend up to $1,000 on permits and portable toilets depending on the size of his event. He would have to get approval from the beach committee, the zoning board and the selectmen. He would have to obtain general liability insurance and arrange a police traffic detail. If the function’s tent was bigger than 10 by 12 feet, he would have to apply for a $100 special permit. And if he put up a sign at the function, he would be responsible for getting in touch with the building inspector to make sure he wasn’t violating local zoning rules.

Mr. Cecilio requested that, for the cost of the permits, he be given a designated parking space for any such event. To this, county manager Russell Smith repeated what had become the county’s mantra for the meeting: “We’re not in the business of creating a venue for private events, we’re just trying to manage the beach.”

Mr. Smith reiterated the county’s position over the phone Monday, saying, “We’re not renting the beach. People were asking what they get for their $100 permit fee. What they get is our permission. Nothing else.”