Emergency crews have been busy in the Currency Creek and Finniss areas on Fleurieu Peninsula, south of Adelaide, dealing with flooding.
Police said some roads were under water and had been closed and heavy rain had also affected houses in the area.
They said Main Road at Finniss and Winery Road, between the Goolwa-Strathalbyn Road and Finniss, had been closed.
Drivers in the region are being warned not to try to cross any flooded fords.
Graham Phillips from Currency Creek Winery said the area had been drenched overnight.
"We look over the causeway for Winery Road and that's pretty much flooded right over, you wouldn't get through there," he said.
"Further down is the Finniss River and that would be I'd say a metre at least across the road.
"My staff have just come into the winery this morning and said they virtually came in from Mount Compass/Willunga area and it was pretty much water across the road all the way through."
There has been extensive rainfall across some southern regions of South Australia and lighter falls elsewhere.
Until 9:00am ACST, Adelaide had recorded 35mm and suburban Belair 67mm, Kuitpo, further south of Adelaide, had 52mm and Mount Lofty had 44mm.
Farmers across Eyre and Yorke Peninsulas received up to 50mm of rain overnight, but much of the northern part of South Australia is yet to see a decent fall for the year.
David Heinjus, from Rural Directions, said the state's major growing regions would be welcoming the rain.
"It'll start to get crops moving and will help particularly the later-sown crops move significantly," he said.
"It's good that we've had a bit of a spike in the price and that's weather related, but I think there's there's nothing like a bit of water.
"You make money out of mud not dust, so it's pretty timely rain."
- Additional reporting by ABC Rural
© ABC 2012
13:39 EST With 28mm already recorded in the rain gauge this month, Alice Springs is having its wettest May since 2004.