Sandra Woods and her family live in a comfortable weatherboard house on an idyllic property in semi-rural Schofields, but it is deemed a flood risk.
The property is surrounded by grazing land and native bush and doesn't look like a flood risk, but is classified as being in the Hawkesbury-Nepean one-in-100-year flood zone.
Quotes for flood insurance for the home have started at $500 a week.
As developers prepare the land surrounding their property for thousands of new homes, this family's problem will soon be shared by many more.
"So we're not covered for floods any more," Mrs Woods said.
"They say it is a one-in-100-year chance, so it didn't seem like it was worth paying that amount for insurance."
The Woods family is taking the risk that a major flood won't happen while they are living in Schofields.
The insurance industry has bet the other way by increasing premiums to amounts that many home owners cannot afford.
Since the Brisbane floods of 2010/11, premiums have skyrocketed for people in flood zones.
The major flood risk for Sydney is the Hawkesbury-Nepean plain, which covers more than 350 square kilometres of Blacktown, Penrith, Hawkesbury and The Hills local government areas.
A report commissioned by the state government last year estimated that a major flood would cause $8 billion in damage, and that more than 26,000 people lived in the flood zone.
But that flood zone covers a great portion of the north-west growth centre.
More than 32,000 homes are zoned in the flood-affected area, in which almost 90,000 people are expected to live.
Bright orange tape already marks a new residential development on the border of Sandra Woods' property.
"It does seem to me a little crazy," she said. "If the insurance companies are willing to put extra on our premiums (because) of one-in-100-year floods, and the government is letting people build there, what extra pressure is that putting on people?
"It's quite unreal that they're willing to do that."
A spokesman for NSW Planning and Infrastructure said: "The potential for flooding risk is fully considered in the rezoning process. Stormwater management infrastructure is also put in place and designed to ensure existing flood conditions are not exacerbated by future urban development."