He suspected water got in through the front of the building.
"It caught us by surprise alright. But no furniture was damaged as they have mostly plastic legs and we had plenty staff working, shifting them out in the backroom."
At NorthAble, water flowed back through four airconditioning system outlets that CEO Noel Matthews believed were connected to stormwater pipes and started dripping down into the offices.
"It happened once before, about six months ago, and we had new carpets and repainted the walls. As the stormwater outlet on the road is blocked, water comes back into the building," he said.
"It's an interruption to our services as we have to find a place for our staff to work from for the remainder of the week."
Across the road, items on shelves at Equipment Plus got wet after water seeped into one of the rooms through the ceiling.
At Harcourts, business owner Debbie Beazley said water got into two rooms but there was no major disruption.
Outside the central business area, a water leak in the ceiling at Noel Leeming at Okara Park forced the manager to pull the plug on the store's power as a safety precaution.