"The board of directors of Severn Trent announces that it has given careful consideration to the pre-conditional possible offer," the group said in a statement.
It added: "The board, having consulted its financial advisers, has unanimously concluded that the proposal continues to fail to reflect the significant long term value of Severn Trent or to recognise its future potential."
Severn Trent had already rejected two previous offers from the consortium.
"If the announced final dividend is paid to shareholders ... Then the proposal values each Severn Trent ordinary share at 2,154.49 pence," Severn Trent added today.
In reaction, the consortium announced that it would not be giving any improved offer.
"No member of the consortium or its advisers has met any of the directors of Severn Trent or its advisers, despite repeated requests," said Michael Rolland, president and CEO of Borealis, commenting on behalf of the consortium.
"In the absence of any such engagement, there will be no further proposal from the consortium and no offer for Severn Trent shareholders to consider."
The consortium comprises Canadian group Borealis Infrastructure Management Inc, the Kuwait Investment Office and British pension fund Universities Superannuation Scheme Limited.
