The 25p charge will cover all the costs to Channel 4 of administering the eviction votes and includes a 10p donation to a charity for each vote cast.
In previous series, Channel 4 had kept a profit from each 50p call, after deducting administrative costs and the 10p charity donation.
Channel 4 said it cancelled text voting because mobile phone operators cannot process SMS votes within a time frame suitable for the voting procedures on the programme.
Andy Taylor, Channel 4 managing director of new media, said: "Cutting costs of phone votes will hopefully encourage the highest possible number of our viewers to interact with the programme."
The voting process will be monitored by an external law firm.
The last series of 'Big Brother' was plagued by allegations of racial abuse towards Bollywood star Shilpa Shetty from fellow contestants Jade Goody, Jo O'Meara and Danielle Lloyd.
Last week, Ofcom ruled that Channel 4 had breached its code of conduct on three occasions during 'Celebrity Big Brother' and has ordered the broadcaster to issue an on-air apology during the forthcoming series.