Before Stacey O’Toole bought her new property in North Richmond, on the outskirts of Sydney, she diligently checked everything she could to ensure it wouldn’t be affected by flooding.
But when Australia’s east coast was hit by a “rain bomb” in early March, it had to be evacuated because two local stormwater dams were at risk of failing.
They didn’t – but O’Toole says “we were very concerned because we thought we’d bought somewhere that wasn’t going to be impacted”.
“We looked at all the data, we looked at the flooding maps as well, and obviously did all the conveyancing that you do when you buy a property,” she says.
O’Toole has lived and worked in north-west Sydney for nearly 30 years and has three properties in the area – making her a seasoned navigator of the flood-prone region.
But the flooding has been getting worse with the area hit with two “one-in-100-year” floods in two years, she says.
“It’s starting to change and places are flooding that have never flooded before, especially around the Pitt Town area. It might be nuisance flooding or local flooding – but it got to a point where it was impassable.
“I’ve never really been concerned with floods before because I know where the water is going to go. [But this time] our main evacuation route went underwater while we were on it.”
Potential flooding presents a dilemma for prospective buyers. In Sydney’s white-hot housing market the Hawkesbury-Nepean Valley proved an opportunity for buyers – although prices surged by up to 45% during the pandemic, according to real estate website Domain.
In Richmond, prices grew by up to 32%, and O’Toole believes the influx of new homeowners aren’t as well informed as they should be.
“A lot of people in the new areas thought the floods wouldn’t impact them but they had power and water cut to their homes because it all comes from the same place,” she says.
“They weren’t particularly educated, they think they are safe up on a hill, but they’re absolutely not.”
There are many blocks of land and properties for sale in flood zones – including in Richmond, Windsor, Pitt Town and Penrith – where the advertisements do not mention the flood risk. None of the real estate agents selling the properties contacted by the Guardian responded to requests for comment.
O’Toole argues communication with prospective buyers must improve.
“People spend a lot of money on those homes, but you can’t change the fact that you are on a flood plain,” she says. “There needs to be a better system for people to actually understand what the dangers are.”
Marcus Claxton, who is building a house on a block of land in the Redbank estate in North Richmond, agrees. He says it should be mandatory for real estate listings to mention the flooding risk.
“If it is in a flood zone, they should have it front and centre, because people may not know to ask,” he says. “If a home is in those flood zones – and long term Hawkesbury residents know those areas – I would strongly advise against buying there.”
Claxton and his wife have always lived in the region and intended to stay – but are worried about the rising flood levels.
“During this year’s flood, the road used for flood-free access actually flooded, which was a bit weird,” he says.
“I was a bit unnerved watching the water rise because it did come a lot higher. They [the authorities] really need to scrutinise what land they make available for building. And they need to rethink the one-in-100 year flood line … we need to go maybe one or two metres above that.”
Chief executive of the real estate institute of NSW, Tim McKibbin, says it is not mandatory to include flood-risk warnings on listings but agents must disclose if a property has been flooded in the past five years. There is no obligation to disclose if a property is on a flood plain.
“It becomes very uncertain because the legislation and the regulation only talks about the past five years,” McKibbin said. “The legislation and regulation are also silent on how agents should disclose that [recent event] information – they only need to demonstrate they have made that disclosure.”
Tom Hubble, a geologist and associate professor at the University of Sydney, says it is “quite reasonable” to expect more frequent and higher floods to hit the region.
“I’m expecting repeat events of floods of similar sizes and possibly quite a bit larger over the next few decades,” he says.
“If I was placed in charge, I would be endeavouring to reduce the number of people that are located in what we would recognise to be flood-prone ground.
“The inherent cyclicity that is probably evident in the Hawkesbury-Nepean Valley, and the specific nature of the channel geometry suggests to me that that’s not the best place to have large urban populations, or even large, semi-urban and semi-rural populations.”
Thousands more people could soon be living on the Hawkesbury-Nepean flood plain if land already approved for development were to proceed, according to planning officials, councillors and the state government’s own data.
The NSW government is pausing new developments while it revises its flood strategy but pressure to open up more land for housing isn’t expected to ease. The Coalition is pursuing a controversial plan to raise the wall of Warragamba Dam which it argues could mitigate some risk.
Hubble says the area has experienced long term cycles where floods then droughts dominate – with each period lasting 30 to 50 years.
He says the lack of major floods in the region between the early 1990s and recent years reflects we are shifting into a new cycle. “If the observation of the flood-dominated regime versus drought-dominated regime is real then we can expect floods as large or larger to occur on a relatively frequent basis.”
The geologist says authorities should rethink planning decisions based on the one-in-100-year flood line and the advice given to people buying land or homes in the area.
“Unfortunately, the geography and the geology of that area means that the one-in-200-year and the one-in-500-year flood and the probable maximum floods are much, much higher events than we would expect to encounter on most flood plains.
“So the probable maximum flood is about twice the height of the one-in-100 year flood in that particular river system down around Windsor and Sackville. And if there is cyclicity in the system, then a lot of our estimates may well be underestimates.”
