SUPER A-Mart staff and CFA crews are working to stop water damage in the storage rooms of the furniture store.
A fire sprinkler was activated when a picker hit a pipe on the roof about 11.20am Saturday.
The water was still flowing at 11.40am.
Staff and customers were evacuated from the premises.
Store manager Brenton Van Gameren said once the sprinklers stopped and water was cleared he would assess the full damage of the situation.
"We don't know how much damage there is until we can get in and have a look," Mr Van Gameren said.
He estimated there would be about $20,000 of stock damaged by water.