BILLERICA — A well-known bee farm must fix a “public health nuisance” or else daily fines from the town would start to sting.

Because Merrimack Valley Apiaries’ swarms of bees have continued to drop excrement at the Gouveia family’s home on Nashua Road, Billerica officials have ruled that the business “unreasonably interferes with the owners use and enjoyment of their property,” according to a notice of violation from the Board of Health.

As a result, the Card family has 10 days to correct the bee issue. The town’s letter states that they can relocate the bee hives and/or take other measures that alter the bees’ flight path, such as planting flowering plants on their land to prevent the bees from flying off their property.

Failure to comply may result in legal action from the Board of Health, as well as a fine of up to $1,000 per day. The Card family is permitted to petition the Board of Health for a hearing.

“I really don’t want to comment,” Crystal Card, co-owner, said on Thursday.

Serry and Mannie Gouveia live at 321 Nashua Road, residing in a “bathroom” because their property happens to be the “toilet” for bees from the nearby farm, they say.

Throughout May and June, the Gouveias say their cars, deck and other parts of their property get covered in bee excrement. They’ll walk outside for a few minutes and have excrement on their shirt or in their hair, they say.

On Thursday, Serry said the notice of violation was “very encouraging news.”

“Hopefully, we can come to a conclusion that’s good for everybody,” said Serry, who has been at the Nashua Road home with his wife since they built it in the early 1990s. They have a 21-year-old daughter and an 11-year-old son.

“It’s a huge step in the right direction, but it’s not over by any means because they have a right to fight this thing,” he added.

The Gouveias say the bees are coming from a 55-acre farm on the outskirts of Billerica, where Merrimack Valley Apiaries operates. The third-generation family business — now among the nation’s largest beekeepers with close to 30,000 hives across the country — was brought to Dudley Road in the 1970s.

During peak season there are 400 to 800 hives, and hundreds of thousands of bees on the Billerica farm.

They raise both the queens and the bees, which in turn produce the honey that they sell. Merrimack Valley Apiaries, established in 1958, produces more than one million pounds of raw honey each year.

“There’s nothing we can do to change the bees’ flight path,” said Glenn Card last month, whose grandfather started the business. “It’s a natural flight pattern where every day they fly to the best source of food. We don’t tell them where to fly.

“What am I supposed to do? Get rid of the bees and this three-generation business, and stop doing what I do?” he said.

The Gouveias, who live a half-mile from Merrimack Valley Apiaries, did not say that the Cards should shut down the business. They’ve argued that the Cards should move the business to a non-residential area.

Glenn emphasized that the bee excrement does not cause permanent damage, nor are there any health risks from it. It’s part of living next to a farm, he said.

Wayne Andrews, vice president of the Massachusetts Beekeepers Association, stressed that there’s no health risk from the excrement, which he described as a light-brown to dark-brown droplet.

The Gouveias say they’ve spent hours cleaning the excrement off their cars and deck. Even after cleaning, the excrement leaves marks on their cars. They “pray” for rain to soften the excrement, making it easier to clean.

“I just want my house back,” Serry said. “I want my land back.”

Town Manager John Curran said he hopes this notice of violation letter entices the Cards to move their bee hives. Merrimack Valley Apiaries has a right to have a business, but they can’t adversely impact surrounding properties, Curran said.

“We need to make sure that residents’ quality of life is preserved,” he said.

Selectman John Piscatelli said it’s important for the business to show they’re working to fix this problem.

“We want businesses to be viable, but we don’t want them encroaching upon residential areas,” he said.

Selectman George Simolaris pointed out that the farm is an important asset to Billerica with open space.

“We need that open space instead of houses there,” Simolaris said. “I’m sure the farm and the neighbor involved, with the town, can work on a resolution.”

Follow Rick Sobey on Twitter and Tout @rsobeyLSun.