Cut water use by 30% says Institution of Civil Engineers
Wales has been warned it should not be complacent over its water supplies, with a call for a cut of almost a third in the amount everyone uses.
Despite recent heavy rain and floods, the Institution of Civil Engineers Wales Cymru (ICE) says the nation consumes and wastes too much water.
It wants universal metering and removal of regulations discouraging water sharing between neighbouring companies.
Welsh Water says it is investing heavily in preserving supplies.
ICE said the public, the Welsh government, regulators and water companies should all contribute to putting Wales in a strong position to face the challenges of population growth, climate change and economic uncertainty.
Keith Jones, the ICE Wales director, said: "It is vital that the whole of society is involved in the process of balancing supply and demand.
"Wales is commonly thought of as a rainy area, however, we must look to the future. Rainfall will be more varied, both in terms of time and location, so we cannot be complacent."
The report recommends changing pricing structures to reflect the "true value" of water.
Currently, most households pay £1 per day for an unlimited supply, which requires a costly treatment process to make it safe to drink.
ICE said it would be "unsustainable" to use expensive, safe to drink water for everything, including watering the garden in the long term.
It calls for a 30% reduction per person.
As well as universal metering, ICE said discretionary tariffs should be introduced to protect the poor.
Welsh Water said it encouraged wise use of water while it was "investing heavily in protecting resources, replacing old pipes and mains, and greatly reducing leakage".
Peter Perry, the supplier's operations director, said water use in Britain compared favourably to many other western countries and the USA.
"We find increasingly that customers are very, very responsive to use water more efficiently," he said.
"We have to get our own house in order with our leakage levels but, supporting customers to use water more wisely, I think there's an emerging social conscience with this.
"We get a great response from customers when we issue information on how use water less."
Earlier this year, seven English water companies announced hosepipe bans and there were calls to move water from Wales to England.
ICE recommended the removal of regulatory barriers that discourage water sharing between neighbouring companies.
Mr Jones said: "ICE does not support a national water grid or long distance bulk transfer. These options would be too costly and too carbon intensive."