Experts say Canberra does not have enough water storage and supply to sustain future residents.

The ACT Water Matters Conference this year focused on the water needs of Canberra in 2050.

Australian Water Association chief Jonathan McKeown says a recently-announced $410 million upgrade to the Cotter Dam may not be enough.

“The construction and the improvements to the Cotter Dam continue to provide Canberra with a water security that it didn't have before,” he said.

“Already the conference has concluded that the capacity we've got now is not going to be sufficient to meet those demands [of a growing population].”

Mr McKeown said the ACT needs to look for supplementary water supplies now.

“The infrastructure capacity that we've got now in Canberra will need supplementation within the next 10 to 15 years,” he said.

“It could be further upstream, it could be augmentation of existing infrastructure or new infrastructure.

“Before the increased demand comes the community's got to be aware of the growing demand and be very supportive of the policy and planning decisions their government makes in anticipation of that increasing demand.

“The best way to ensure you've got a community behind the kinds of developments you need for our water requirements is to ensure the community is fully engaged with what the options are and what the increased demands are likely to be and understand the implications for the way they live in the city of Canberra.”