Two years ago, the NSW government drew a hard line in the sand. No more building on high-risk floodplains. The message from Planning Minister Paul Scully was blunt: approving new homes in these areas could put lives at risk. Better to disappoint landowners now than console families later.

Fast-forward to 2026, and that conviction is looking a lot softer.

The government has now approved a scaled-down version of the long-running Marsden Park North proposal in Sydney’s north-west — 960 new homes, plus a substantial employment precinct — smack in the Hawkesbury-Nepean Valley. This is the same floodplain the state itself has repeatedly described as having Australia’s highest unmitigated flood risk.

This isn’t a new site. Developer Leamac first floated plans more than a decade ago for up to 6000 homes housing almost 20,000 people. That proposal was rejected after flood evacuation modelling showed it would nearly double the average annual number of people exposed to flood risk across the catchment.

In October 2023, the government publicly refused the rezoning. The language was unequivocal. Flood evacuation routes were inadequate. New development would worsen congestion during emergencies. Lives would be put at risk.

So what’s changed?

Officially, the answer is scale and design. The new proposal is far smaller, with housing pushed to higher ground and much of the precinct earmarked for employment uses. Homes are set above the one-in-100 Probable Maximum Flood level, with an additional climate change buffer, effectively planning for a one-in-500-year event.

In theory, that sounds conservative. In practice, the maps still tell an uncomfortable story. Large parts of the precinct would be inundated in the largest conceivable flood. The area is hemmed in by creeks to the east and south, and further development inevitably adds pressure to evacuation routes used by upstream communities like Windsor.

Even without any new rezonings, flood modelling completed in 2023 showed risk to life in the Hawkesbury-Nepean Valley is already increasing due to previously approved developments. Adding nearly a thousand more homes doesn’t reduce that baseline risk — it compounds it.

Blacktown Council, while broadly supportive of the employment component, has been explicit about the gaps. Critical transport and evacuation infrastructure remains unfunded. There is no clear mechanism to pay for repairs to community facilities that are expected to be damaged in future flood events. These are not minor details; they are fundamental to whether the development can function safely.

The broader context is the housing crisis. Governments at every level are under pressure to unlock supply, and Western Sydney continues to carry a disproportionate share of that burden. But urgency does not magically rewrite geography. Floodplains don’t become safe because the housing market is tight.

There’s also an uncomfortable political overlay. Leamac is a client of Iemma Patterson Premier Advisory, co-founded by former Labor premier Morris Iemma. Parliamentary emails show sustained lobbying efforts, including direct correspondence with the premier expressing frustration at delays. Minutes from a June meeting record the developer seeking “continued support” to overcome departmental resistance due to flood risk.

The government insists the revised plan aligns with flood inquiry recommendations and has been shaped by expert advice. The Insurance Council of Australia, meanwhile, has issued a stark warning: more than 240,000 Australian homes already face severe to extreme flood risk — and we should not be adding to that number.

At its core, this decision exposes a familiar tension in planning. The rhetoric says safety comes first. The reality says compromise, pressure and incremental backsliding.

Marsden Park North may be smaller than originally proposed, but the principle hasn’t shrunk. Once again, Western Sydney is being asked to absorb risk — environmental, financial and human — in the name of growth. And once again, the hardest question remains unanswered: when the water rises, who really carries the cost?