The old empty house at Waipiro Bay, near Te Puia Springs, was washed away last evening.
The area around the building had been damaged by the initial rainfall earlier yesterday.
The nearby town of Tokomaru Bay, 89km northeast of Gisborne, and its surrounds have been the worst hit after the initial rainfall of up to 230mm in just a six-hour period hit the area.
Anaura Bay, like Waipiro Bay, has also been badly damaged by the flooding, including the only road out of one part of the area being cut off by huge slips of mud and trees.
Weather stations in Gisborne in the 24 hours to last night had recorded between 250-300mm of rain.
Tairawhiti Civil Defence group controller David Wilson said the big message last night was for East Coasters in the hard hit areas to be prepared and be careful.
Tairawhiti Civil Defence declared a state of emergency, and some residents described conditions as the worst since Cyclone Bola in 1988.
More damaging rain — potentially up to 200mm — was forecast for last night.
There have been no reports of serious injury, but officer in charge of the Tolaga Bay Fire Station Andrew Shelton said two incidents could have turned tragic.
"Our first callout was at 1.55am to assist with a job in Tokomaru Bay after a person was swept into the river," he said.
"We were unable to get to the job due to floodwaters and washouts. We then had to deviate back due to slips.
"The person was found alive and well."
About four hours later the Tolaga Bay fire crews were involved in a dramatic rescue of eight road crew workers trapped by the rising floodwaters.
Initially, a large truck was dispatched to help the group, but then they got caught out by rising water levels.
Mr Shelton described it as a "critical rescue".
"Two were airlifted out to safety after being trapped by the water," he said.
Another six were pulled out by surf life-saving personnel.
"They were all very lucky."
Large slips featuring trees, rocks, mud and other debris have come down over sections of SH35 — the route that connects Gisborne to Opotiki via the East Coast.
Mr Shelton said locals were now bracing themselves for the potential impact of the next bout of heavy rain.
"But we have a good team ."
Yesterday morning, Emergency Management Minister and MP for the East Coast Kiri Allan said 150 people were evacuated overnight in the Tairawhiti region.
Ms Allan had spoken to Gisborne Mayor Rehette Stoltz and told her the Government was ready to offer support as needed.
Ms Stoltz said Tokomaru Bay had been "cut in half" due to damage on the bridge and authorities were working to get supplies across to the other side.
There had been "a lot" of damage to properties in the Tokomaru Bay region, including some that had only recently been fixed up after flooding last June.
"Tokomaru Bay has a lot of damage, and it’s water through homes, not just in the front yard."
By Neil Reid
