The water company is proposing taking water out of the Thames at Teddington Weir and diverting it to Lee Valley.
The missing water would be replaced with treated sewage from the Mogden plant in Isleworth.
Thames Water says this is a vital scheme to address water shortages after 2030.
Council leader, Gareth Roberts, has told a meeting the authority will resist any plans it considers damaging to its land.
The Council has agreed to call on the Government to require Thames Water to reexamine and publish other schemes.
As the planning authority, Richmond Council could have a say in the project going ahead.
Current timelines indicate planning proposals will be submitted in 2026.
