Almost a year after the country's most costly natural disaster, the hardest-hit areas in northern New South Wales are grappling with a future where many homes, businesses and even local councils are uninsurable.

The weather event, which caused record-breaking flooding, has been ranked the fourth most costly natural disaster in the world for 2022 – and the second most costly for insurers.

The Insurance Council of Australia says it's the most expensive in its history – with insurance losses totalling $5.7 billion.

Almost 12 months after the February 28 flood, Lismore residents Lennon Allen-Bartlett and his partner Sophie Adams are still living in a caravan after their home was inundated to the ceiling.

The couple have home insurance, but like many in this high-risk area, they opted out of flood coverage due to costly premiums.

"Per year it's about $16,000 for flood insurance — so there's not many people who would be able to afford that," Mr Allen-Bartlett said.

It means their home is covered for stormwater damage, but not for flooding that comes from the nearby Wilsons River.

The record-breaking Lismore flood peaked at 14.4 metres in the afternoon of February 28, 2022.

But the couple maintain their property was already inundated with clear stormwater runoff the night before.

"It was torrential rain all day and all night and there was clear water under the house up to our knees already at 6pm the night before," Ms Adams said.

The pair lodged an insurance claim with Allianz, hoping it would compensate them for stormwater damage to the laundry, work shed, pool, gardening and camping equipment and downstairs walls.

But Allianz denied the claim, commissioning a hydrologist's report which found "the damage to the property was due to floodwater inundation" from the Wilsons River, and not stormwater.

But right next door at his parents' place, the same insurance company came to a different conclusion – accepting stormwater had inundated the house "up to 200mm above the floor level".

In the next house, Michelle Cormick also had a similar policy with Allianz.

The company offered to cover her for 200mm of stormwater damage - but only at ground level below her house, which is about two metres less than her neighbour.

"You hear other houses getting payouts for stormwaters and we've been denied, it's pretty heartbreaking," Ms Adams said.

In a statement, Allianz said:

No insurance claim is the same, and each varies in its individual circumstances and complexity.

Allianz appreciates the ABC bringing to our attention the different outcomes our customers received in relation to the assessment of how rainwater run-off may have impacted these three properties.

As a result, we are undertaking an in-depth reassessment of the relevant hydrology reports and circumstances of the customers you have brought to our attention.

Not an isolated case

In the past 12 months, Legal Aid NSW says it has received more than 4,000 calls for support from flood-affected residents in the Northern Rivers.

Disaster recovery Senior Solicitor Ma'ata Solofoni said almost half of those had been about insurance.

She said one of the main issues was whether damage to homes was caused by stormwater or riverine flooding.

Ms Solofoni said insurance companies were entitled to have expert witnesses, like hydrologists, make assessments but evidence from clients was just as crucial.

"The thing with hydrology reports is they [hydrologists] often come in days or weeks after an event and gather information that's available to them and make their own sort of opinion of what happened," she said.

"Evidence from clients, their eyewitness testimony, is just as crucial because they can say, 'Well actually this is what happened and this is the times that it happened', so any evidence from the clients can really make a difference in their claim."

Ms Solofoni said a recent determination by the Australian Financial Complaints Authority had found in favour of the clients who provided photographic evidence that showed stormwater had been through the property before floodwater.

Business owners must 'self-insure'

It's not just home owners who are grappling with flood insurance.

Even before the record-breaking February flood, many Lismore business owners said full flood coverage was either beyond their means or not available at all.

Janice and Graeme Palmer, who own a gift shop in the CBD, said many business owners, including themselves, did not have flood insurance and would instead lift their stock higher than previous flood peaks to avoid major losses.

But the record 14.4-metre flood caught almost everyone by surprise.

"The building itself – yes it gets muddy and wet but all the materials here are waterproof."

Flood leaves local councils uninsurable

Two local councils are now uninsurable after dozens of public facilities were flooded, resulting in tens of millions of dollars in damages.

The Lismore City Council, which is home to the country's most flood-prone postcode, said its insurer "will no longer offer flood insurance for its property and artworks assets."

Tweed Shire Council's General Manager Troy Green said the cost to re-insure for flood damage was now on par with any potential payout.

"Unfortunately, our risk profile has changed from an event that might happen to a foreseeable event," he said.

Mr Green said the council had decided "the best use of public funds" would be moving assets out of the flood path.

"We're looking at strategies where we can relocate our core assets out of the flood plain and the assets that we can't relocate, we're looking at measures where we can harden those and make them more resilient to flooding," he said.

'Something has to change'

It's not just local councils grappling with uninsurable assets.

Four Catholic schools are considering relocating after an insurance company told the Lismore Diocese the schools would need to make changes in order to receive coverage, which is required by law.

State member for Lismore Janelle Saffin said "something has to change".

Head of the Insurance Council of Australia Andrew Hall said governments need to correct the poor planning decisions of the past in order to fix flood insurance for the future.

"It's very hard to design a product that can provide the sort of coverage that people are looking for, which is why we are talking to government about how we can flood-proof Lismore [and] how we can better protect homes," he said.

The process to buy back homes in the hardest hit areas is already underway as part of the Resilient Homes package.

But the process will likely take years, as will any large-scale flood mitigation works.

Mr Hall said in the short-term, flood insurance for residents in high-risk areas would be "very expensive".

The Federal government has allocated $22.6 million to identify the biggest insurance issues in high-risk areas like Lismore through its Hazard Insurance Partnership.

The aim is to develop measures — in consultation with industry and stakeholders — to make insurance more affordable over time.

Meanwhile, those living in harm's way like Lennon Allen-Bartlett and Sophie Adams have few options but to hope they don't get hit by another flood.

"How can we live somewhere that we can't get insurance for? We're just going to have to keep doing it again and again," Ms Adams said.

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