The Dunkls are water people.

For the past 14 years, Frank, Peter and Heidi Dunkl have owned, operated and delivered Chilmark Spring Water. But now the siblings are looking to sell the business.

“When you’re almost 70 and you’re dealing with one five-gallon bottle in your hand and another on your shoulder and you have to walk up three flights of stairs, you think, what am I doing this for at my age?” Frank Dunkl said. “You know what I mean?”

Operation can produce 400 bottles per minute. — Ray Ewing

The water originates in a spring on their land in the woodlands off Old Farm Road in Chilmark and is trucked to their small bottling plant at the airport business park. The three siblings share responsibilities, ensuring everything is done with precision and safety.

The local bottled water business “is not what you call a big money-making venture,” admitted Frank. Chilmark Spring Water is in direct competition with some of the “biggest corporations in the world,” he said, including Nestle Corporation, Coca Cola and Pepsi.

To compete the Dunkls created custom labeling for local retail outlets such as Net Result, Reliable Market and several hotels on the Island.

“It’s our forte because the three of us are all trained and experienced commercial artists,” Frank said.

They are also stained glass restorers, carpenters, fierce conservationists, French horn players, organic gardeners and vegetarians.

“We are a group of wacky bohemian artists,” said Frank. This isn’t just a turn of phrase, either. The siblings were born in Prague and their family roots trace back to the ancient kingdom of Bohemia.

For the Dunkls, public health and safety has always come first. At the height of the season, Chilmark Spring Water can produce 400 bottles a minute, and every bottle is the same as the first.

“Nothing in our water needs to be filtered, but when in Rome do as the Romans do . . . that’s why in 14 years of operation we never had a single bottle of our water come back with any sort of contaminate, and we’ve put out literally millions of bottles,” Frank said.

The pristine water goes through a carbon filter “so it’s crystal clear and [has a] uniform flavor,” Frank explained. “In nature the flavor of water changes with the seasons.”

The bottled water also goes through an ozone generator to sterilize the water, the bottle and the caps, giving it a two-year federally-approved shelf life.

“That’s the unit that guarantees you’re not going to have anyone get sick on our water,” Frank said.

“We don’t only comply with the law; we try to comply with the intent of the law, and that’s why we’ve never had a problem,” he continued.

The siblings have enjoyed working with each other. “Oh, we don’t have any problems,” said Heidi.

“Whether fortunately or unfortunately, none of us are married,” Frank added. “It’s unfortunate that we don’t have any youngsters coming up to help us with the physical part, but it’s fortunate because none of us are married and we don’t have those family issues that could draw us apart when it comes to unified business policy. We live together, we sit down at the dining room table, we eat together.”

Custom-made labels helped increase business. — Ray Ewing

“And we hash it out,” Heidi said.

“I’m not saying everything is smooth and harmonious. There are differences of opinion, and it’s a good thing, too, because . . . you need checks and balances,” Frank said.

The Dunkls have never focused solely on water, though, making time for intricate carpentry jobs.

“We are restorationists; we only deal with antiquity,” Peter said. The family has done restoration work at the Dr. Daniel Fisher House in Edgartown, The Flying Horses in Oak Bluffs and this week was working on benches for the Martha’s Vineyard Camp Meeting Association.

But an appreciation for nature and “respect for a natural lifestyle” is also deeply rooted in the Dunkls history. Their property abuts the Roth Woodlands and sits squarely at the head of the Mill Brook watershed. Frank said the family is “maniacal” when it comes to all things conservation.

Interested buyers would gain access to their land and right of way to the spring.

The Dunkls are quick to point out the benefits of groundwater sources versus surface water, the differences between artesian and well water, and the distinction between bottled European water and American water. The exhaustive knowledge of their water and the land that surrounds it comes from a place of deep passion and purism that they hope the next stewards of the company will honor.

“We have to try and look at the future for the Vineyard for society and the community out here, as well as the Island economy, to try and balance all these things out . . . and see what’s practical,” Frank said.