The highlight reel of the June pool party in Upper Marlboro, Md., featured all the makings of a splashy summer event: burgers sizzling on a grill, DJs spinning out beats and a throng of revelers in bright swimsuits.

While guests considered the house party a classic way to kick off the season, Prince George’s County officials sizing it up saw a multitude of hazards: a public event on private property with no crowd control, booze being served without a system to prevent underage drinking and potentially drunk swimmers in a pool without a lifeguard.

That official view led the county liquor board to slap a $7,500 fine on the owner of the party house on Willoughby Road for operating a “bottle club” without a liquor license and creating “a threat to public health, safety and welfare of the community.”

The fine, issued last week, is one of the largest monetary penalties the county has issued in its ongoing crackdown on unregulated for-profit house parties.

The $7,500 fine is significant, said Maj. Chuck Hamby of the Prince George’s police. Often, such parties are found to have violated only zoning ordinances, resulting in a fine of a few hundred dollars — a small cost of doing business for an event that could net at least $10,000 in a night.

“This was really successful because it really cut into the amount of money that they could make,” Hamby said.

Hamby said undercover officers bought tickets as members of the public and attended. They were given wristbands and were patted down, and they found themselves among 300 partygoers who were buying bottles of liquor and food from the buffet.

The homeowner, Sharon Taylor, said that the county unfairly targeted her and that she plans to fight the fine. Taylor said she worries that the enforcement push on house parties is one way for the county to drive out affordable entertainment options for the black community.

“A lot of things were exaggerated,” Taylor said.

The recent fine highlights a continuing clash between county officials who want the unregulated events to disappear and party promoters who say Prince George’s is trying to drive out vibrant nightlife.

Advocates of house parties, which are often advertised on social media and charge an admission fee, say the events allow homeowners to make money and promoters to put on exclusive events that otherwise were fading away after the county’s previous push against illegal nightclubs.

The county, however, fears that house parties attract violence and upset quiet residential communities not designed for hordes of rowdy partygoers, parked cars choking streets and music booming at all hours.

“We’re concerned about these because historically in the county, we’ve had a lot of violent crime that grows out of these from people who’ve had too much to drink,” Hamby said. “The worry is that we end up with somebody shot.”

That happened in 2013 and 2015, when two young men were fatally shot at separate unregulated house parties. In each case, the men were not the intended targets. Their killings remain unsolved.

According to Hamby and online fliers advertising the June 4 “Afro Caribbean Pool Party” — which netted the $7,500 fine — promoters were charging $10 for early bird tickets and $20 at the door. Promoters also promised food and drinks for sale at the event.

County officials and police went to the home the day the party was scheduled to tell people on the property in advance that the event was unregulated, Hamby said. But police couldn’t legally shut it down beforehand, Hamby said.

The same day, undercover officers went to the address, where by then the party was in full swing.

Although there was a sign on the front entrance that said it was a private event, it was clear that anyone could buy admission, Hamby said.

Taylor, the homeowner, said the event she was fined for was meant to be a free, private fundraiser held by a co-worker she allowed to use her home.

And Taylor said she submitted sign-in sheets from the party to county officials that showed guests had signed a paper saying they did not have to purchase a ticket for the event or pay an entry fee.

Taylor contends that there were about 80 people at the party, not hundreds. And she said that although she left the party, she was there when it started and security and lifeguards were present.

But Hamby said that despite whatever safety measures homeowners take, they must have proper permits and licenses to hold such events.

The County Council is considering legislation to clamp down on the unregulated parties.

The proposed legislation would allow the police department or a county code inspector to “issue an immediate order to cease and desist the prospectively planned prohibited activity.” The county also is working to increase the financial penalties a homeowner can face for allowing the events on their properties.

“Hopefully, word will get out that it costs more in fines than you’re making,” Hamby said. “So hold the parties the proper way, or don’t hold them in Prince George’s.”