Bravo has secured its Hamptons home base for the upcoming third season of “Summer House,” but Page Six has exclusively learned that neighbors who recently purchased mansions nearby were blindsided by filming notices for the party-filled reality series.

“Not one of the buyers was advised before closing that their multimillion-dollar retreat is next door to where a trashy reality TV show is being filmed,” a resident of the quiet gated community tells us.

We’re told that three families with children and grandchildren bought properties over the last 12 months adjacent to the “Summer House” rental in Water Mill, Long Island. This is the second year the show — which has previously been likened to a “Jersey Shore” of the Hamptons — is filming in the same house.

“They are not happy,” the source tells us. “Apparently, [one family] watched the show and are now worried that their 3-year-old grandchild will be watching people having sex in the woods.”

The filming permit, obtained by Page Six, reveals that shooting will begin the weekend of June 22 and will continue every weekend through Labor Day. Between the cast and crew, there will be a total of 35 people on the property per day during the 40 days of filming.

The permit describes the show as “a comedy/docuseries filming a group of friends at a residence,” and reads, “All filming will take place within the house and property of the house … We will be filming at the house 12 hours or less a day.”

Neighbors last year were more forgiving and told us they were “optimistic” the cast would be on their best behavior, saying producers assured them noise and traffic would be kept to a minimum.

This isn’t the first filming issue the show has run into. Over the past three years, residents and businesses in Montauk and East Hampton have banned the series from filming at various locations, including Hamptons hot spot Surf Lodge. After the first season of the show, East Hampton denied Bravo a filming permit, forcing the crew to move to Water Mill, a hamlet of Southampton.