Farmers considering buying water from the proposed Ruataniwha Dam have about two weeks to make their decision.
Hawke's Bay Regional Council's Investment Company (HBRIC) said whether 45 million cubic metres of water was contracted would decide whether the $600m scheme goes ahead.
Recent figures showed HBRIC had just over 30 million cubic metres of water contracted.
HBRIC said new foundation water user agreements had been sent out to farmers with the revised water price of 27.5 cents.
The deadline for farmers to sign up as a Foundation Water User was 18 April.
HBRIC has had several deadlines in the past for farmers to sign up and all have passed without achieving the minimum amount of water sales required.