At stake is the future of the siblings', Maureen and Louis Downes, long-term family home in Bull Street, Maitland.

For years the Downes have been claiming that since the two-storey NSW Infringement Processing Bureau and adjoining car park were built behind their property almost 20 years ago, they have suffered flooding problems.

The legal dispute centres on a claim by the Downes that alleges council's approval of the $2.48 million development in 2001 negligently exposed them to risk of harm caused by disruption to drainage on their property.

Further, the pensioners - both in their 60s - allege that the council created a nuisance, which adversely affects the use, enjoyment and value of their property.

Mr Downes told the Newcastle Herald this week if the pair lose at trial and are ordered to pay the council's legal costs, they would be forced into bankruptcy and lose the house that has been in their family since the 1920s.

"We have been fighting this for years and we are not giving up," Mr Downes said

"This place has been in our family for as long as anyone can remember. Our uncle used to own it and we spent a lot of school holidays here as kids growing up."

Maitland council applied to the Supreme Court in March to have the compensation claim thrown out, but this week Justice Christine Adamson ruled the matter should go to trial.

The court heard Justice Adamson made her decision after reviewing a joint court book of evidence prepared by the council's solicitors, Moray & Agnew, detailing the lengthy saga.

While none of the evidence has been tested under cross-examination, the Downes claim their property is regularly flooded because the development altered the course of stormwater runoff into their backyard from higher ground.

They allege their modest two-bedroom house is sinking, several timber piers are rotting, doors don't close and walls are cracking.

"Since the construction of the building and the car park, the plaintiffs' uncontroverted evidence is that the property has been affected by water from the southern side of the gully [behind the house]. Storms produce this effect without a flood," Justice Adamson said.

"Every time there is a storm, the plaintiffs' property is affected by water coming from the direction of the Infringement Processing Bureau. The gully itself has also overflowed on several occasions, some of which have been documented by Ms Downes."

Lawyers for the council argued the case should be dismissed because it "acted in good faith" and followed the usual process of consultation and consideration in approving the car park.

But the court heard that when the council was considering the development, it wrote to three members of its Floodplain Management Committee in June 2001 informing them of the proposal.

Member Michael Belcher wrote back outlining his fears.

"I am concerned that a bad decision to allow development over an existing watercourse [the previous construction of a shed in the area in the 1990s] will be compounded by this significantly more substantial development," he wrote.

"While it is outside the floodway it is an extremely vulnerable site in the event of overtopping."

The court also heard that an engineer raised concerns in July 2001 that construction of the car park would add addition hard surfaces to the site.

"Inspection of the downstream watercourse has revealed that there is a rise in the topography and therefore the additional impervious area is likely to add to the existing 'soggy' problems in this area," the engineer wrote.

"In order to maintain the existing hydrology the car park would only be permissible using previous pavements."

Justice Adamson said instead of accepting its own engineer's advice, the council approved the development on the basis that there would be an "approved stormwater drainage plan", which assumed the car park would be covered in an impervious surface.

She found the Downes had provided substantial photographic evidence to show the change in topography of the land behind their property.

"Further, the plaintiffs have adduced uncontroverted evidence that the conditions imposed by the council on the development have been manifestly inadequate to address the drainage issues," she said.

"In essence, the plaintiffs submitted that their concerns about the damage which would be caused to their property by the car park which were foreseen by Mr Belcher, were disregarded by the council, and have come to pass."

Mr Downes acknowledged that neither he or his sister were capable of running a trial in the Supreme Court against the council's lawyers.

He said the siblings were hopeful of finding a lawyer to act on their behalf on a pro bono basis.

To date, the pair have been assisted in getting the matter to court using free advice provided by the Hunter Community Legal Centre.

Justice Adamson found the siblings would normally be entitled to have council pay their legal costs for the dismissal motion, but because they represented themselves no cost order was made.

"It's been terribly stressful," Ms Downes said. "We just want a fair go and for our side to be heard in full."

The matter has been listed for a directions hearing next week.

While you're with us, did you know the Newcastle Herald offers breaking news alerts, daily email newsletters and more? Keep up to date with all the local news - sign up here

IN THE NEWS: