A school attended by children from Watford with severe learning difficulties needs to raise £1million for a new hydrotherapy pool.
Woodfield School is trying a new fundraising approach and asking for just £2 per person - but needs 500,000 people to donate to reach its target.
Woodfield Association School Partners, the charity which raises money for the school, has said the current 37-year-old pool "has reached the end of its life and is no longer viable".
The charity is hoping families may want to hold a dinner party or local companies may hold a cake bake in its name.
Beverley Hamilton, of the school, based at Leverstock Green, said: "Woodfield School caters for up to 68 pupils from the Dacorum and Watford areas who have severe disabilities.
"We have plans drawn up and have had an estimate of just over £1million to build a new sports hall and hydrotherapy pool.
"Unfortunately this is not something that the local authority will provide.
"We are not expecting large cheques from individuals or organisations but rather feel that if enough people gave up the cost of a cup of coffee, i.e. £2, then we would reach our target if we reach enough people."
Should Westfield reach its £1million target, the huge redevelopment project will rebuild the school pool in a building that’s not too hot in summer and too cold in winter, make the pool larger and install new plant systems.
The school is also looking to improve the changing facilities and pool surrounds, have a pool that will encourage pupils to enjoy swimming and have a pool that can be available for the local community to use out of school hours.
Those behind the massive fundraising initiative added: "Any donation, big or small, will make a difference to the opportunities and experiences for our pupils.
"A £2 donation is less than a cup of coffee at your favourite coffee shop, less than a pint of beer or glass of wine.
"Naturally we have to set a time limit on our fundraising and whilst we will endeavour to raise the money needed for a new build, we have to be realistic and, if by the end of 2015 it is not going to be possible, all monies raised will be used to up-grade our existing pool."
To make a donation to the school visit www.justgiving.com/w-a-s-p.