Luxury houseboats and floating restaurants have deserted Windsor's wharf for safer moorings
Further upstream, at Wisemans Ferry, prawn fishers have stopped work due to safety fears.
"We're watching the tide, and some of the fishermen have started to come back home," says Mary Howard, 66, whose family has been fishing on the Hawkesbury for as long as she can remember.
"We're lucky we've built our house above the ... flood zone, but we're still watching closely.
"We have two boats and a pontoon that can withstand high tide.
"We are not yet threatened, but the nuisance of this flooding would mean we can't go to shop and our roads will be cut off."
The Playground Weekender, an annual big-ticket music festival scheduled to be held from Friday through Sunday at Wiseman Ferry's Del Rio Resort, was cancelled on Thursday.
About a dozen music fans in Wisemans Ferry for the festival are being billeted at the resort.
Resort manager Bunny Roberts says no one has checked out despite early warnings by the SES.
"We have about 16 local residents ... and a number of visitors to look after, so we have emergency contingency plans put in place at this very moment," she said.
The Hawkesbury SES has told caravan park residents along the Hawkesbury River to watch flood levels closely, be ready to move their vans to high ground and keep in contact with fellow park residents and management.
Some locals expressed concern about possible sanitation problems at some caravan parks on the river, saying on-site effluent treatment plants could be damaged by floodwaters.
- AAP