Average South Australian household water bills will increase by $80 each year to help pay for $1.5 billion worth of new mains water and sewerage connections to rapidly-growing Adelaide suburbs.

SA Premier Peter Malinauskas said the bill hike, to come into effect from July 1, would address a "major underinvestment in water infrastructure", which he said was holding back the construction of new houses.

The SA government will also spend $440 million on new water infrastructure, and restructure developer augmentation charges, to ensure SA Water can cater for housing demand.

"We're calling on households who can't afford much to pay a little bit more for their water bills," Mr Malinauskas told a crowd of just under 1,000 property sector representatives.

Mr Malinauskas said the government needed to spend $1.5 billion over four years to ensure SA Water could service a potential 40,000 new allotments across the state.