The tycoon broke off from the race for the White House to issue a lengthy statement attacking Molly Forbes for claims made in a new documentary.
Montrose filmmaker Anthony Baxter is launching You’ve Been Trumped Too in the Unites States this week.
It revisits the long-running feud between Trump and Mrs Forbes, her son Michael and his wife Sheila, including claims that she has been forced to fetch water from a stream in a wheelbarrow to bathe herself and flush her toilet.
Mr Baxter has billed the film “a unique look at a globally-historic election and a timeless tale of the unlikely encounter between a salt-of-the-earth Scottish family and one of the planet’s richest and most controversial figures.”
However Mr Trump’s company today branded the allegations in the film “highly offensive, defamatory and categorically untrue” and insisted the water problems the Forbes family have suffered have been down to a make-shift well they created.
The documentary claims the Forbes family has suffered from a campaign of intimidation and bullying at the hands of The Trump Organization, which won permission from the Scottish Government to build the golf course after its plans for the Menie Estate, near Balmedie, were rejected by councillors.
Mrs Forbes is shown in the film saying: “He promised the world. It never happens. Never trust Trump. I pity America if he’s President.’
Mr Forbes is filmed declaring: “When he first came to Scotland it was a bit like America - half was for Trump, the other half wasn’t. But now you’ll find that nothing’s happened with what he said so 90 percent of Scotland hates him.”
Green MSP Andy Wightman, who also appears in the documentary, says that Mr Trump “seems to have no respect, not only for Molly Forbes and his neighbours, but he has no respect for the legal framework.
He added: “He’s quite content to preside over a situation whereby he is in effect denying a neighbouring landowner of their legitimate supply of fresh water.”
The statement, issued by Trump International, insisted that an underground pipe “unintentionally disrupted” by a contractor five years ago was repaired immediately.
It added: “We have never, and would never, conduct the type of activity claimed by Molly Forbes.
“These allegations are highly offensive, defamatory and categorically untrue. We are entirely focused on delivering a five-star golf and leisure experience for the public and enjoy a great relationship with all of our neighbours with the exception of the Forbes family and a few others who have fought the project since its inception.
“We have repeatedly refuted the allegations regarding the Forbes water supply. Molly Forbes’ son, Michael, is the joint owner of an antiquated, make-shift ‘well’ located on Trump land, the maintenance and operation of which is not the responsibility of the company. His mother lives in a caravan next to his house and relies on his water supply.
“Over the years, Forbes has personally dug up his well, dislodged and broken pipes and subsequently blamed the company.
“Trump International has sought legal counsel and will pursue legal action against those who have propagated these highly defamatory claims.”
However Mr Baxter said: “The events depicted in You’ve Been Trumped Too speak for themselves. By its own admission, the Trump Organization’s workers cut off the Forbes’ water supply. Molly and her family spent years without a safe reliable water supply.
“I would encourage Donald Trump or any members of his family to come to the opening of the film of You’ve Been Trumped tonight in New York City, where they can see the evidence for themselves.”