The Victorian Farmers' Federation has challenged the Government to start a feasibility study into linking Melbourne's two major water recycling plants with more suburban regions before the November state election.

VFF president Andrew Broad said the land reserves set aside for the metropolitan ring road were the perfect route through which to connect the two treatment plants - located at Werribee and Carrum - with growing suburban belts.

Mr Broad said such a ''nation building'' project would enable homes to be fitted with dual systems where recycled water would be used for gardens and other non-consumptive uses.

He was unable to say how much such a plan would cost, but he urged the Government to investigate it fully so that less treated water was wasted.

Melbourne recycles a larger volume of water than other Australian cities, yet still pumps the majority of its treated water to the sea.

Mr Broad said greater recycling of water in Melbourne would be preferable to taking more water from country areas, as will happen in coming weeks through the north-south pipe.

Stephen Moynihan, a spokesman for Water Minister Tim Holding, said the Government had invested in water recycling, particularly the $380 million upgrade of the Eastern Treatment Plant at Carrum.

Mr Moynihan said water authorities were gradually finding more opportunities to reuse treated water on land.

''South East Water and Melbourne Water have identified potential projects to use up to 40 billion litres of the recycled water over the decades to come,'' he said.