Jan Garill said some families were still living apart and people had lost their jobs and been left homeless as a result of the winter flooding.
She is chief executive of the Two Ridings Community Foundation which is managing the York Flood Appeal.
In the aftermath of the floods it raised £1.3m with match-funding from central Government.
Speaking at an event thanking donors she said: “Grants can replace essentials, but returning home is just the start of recovery for many residents. The stress and anxiety people are still suffering is unimaginable. We have seen families living apart, people losing their jobs - and even made homeless. Many are left with ongoing health and mental health problems.”
However she thanked people for their support and told how it was helping in the recovery effort. Ms Garill added: “The generosity of corporate donors and individuals has made an enormous difference to how we can help residents rebuild lives that were devastated on Boxing Day.
“As well as giving grants for essential household items, our whole ethos is to be helpful, supportive and understanding of people’s circumstances.
“That means we do home visits, get to know people and help them get support from other services .”
Ross Done, who lost everything when his basement flat, in Huntingdon Road, was flooded and is now re-housed in Foss Way, said: “I don’t know how I would have found the money myself to replace what I lost.
“The fund provided me with essential white goods and basic furniture. However, it was more than just financial help - the team at Two Ridings Community Foundation helped give me some mental stability.
“The flood knocked me back and I’m just beginning to see light at the end of the tunnel.”
Nestlé, one of York’s biggest employers, donated £100,000 to the appeal fund. Dame Fiona Kendrick, the firm’s chairman and chief executive said: “As one of the city’s largest employers, we care deeply about the communities in which we live and work and that’s why Nestlé donated to the York Flood Appeal.
“In a tight-knit community like York, it comes as no surprise that many of our employees knew of someone affected by the floods. Many of our people from Nestlé provided practical support in the delivery of vital supplies such as coffee, pet food and bottled water in the immediate aftermath.
“Our aim was to help people affected to get back on their feet and to rebuild their lives and their homes after this awful natural disaster.”
The winter floods left a £1.3bn insurance bill.
Many businesses in affected areas are now unable to get any insurance cover or face massively inflated premiums.
Last week MPs warned that communities in flood hit areas of Yorkshire were being let down by the Government being too reactive to flooding and failing to plan long term.
The warnings in the Environmental Audit Committee’s report followed storms in December and January that caused severe floods in the north of England, Wales and Scotland and Northern Ireland.
York’s Foss Barrier, which was opened and caused 600 homes to flood when it was overwhelmed by flood water, is a cautionary example of what can happen when ageing defences fail, the MPs report said.