Collapse fears for Adelaide Hills dam

The SES, SA police and SA Country Fire Service have been working overnight to notify households of the risk.

Roads have been closed to support community safety and officials are continuing to monitor the condition of the dam.

The SES is also lowering the water level through the excavation of a spillway and pumping. 

"This has the potential to release water which may exceed the capacity of the drainage system of Echunga, which may cause parts of Echunga to flood," it said in a statement on Wednesday.

A sandbag collection point for local residents has also been established at the Echunga CFS station.