LIHU'E, Kaua'i — County officials have launched an investigation into whether homes and other structures lost in Tuesday's fatal flood were properly permitted and were built outside the flood zone.

"We're doing the research," said Sheila Miyake, chief inspector for the county Planning Department.

The Kaloko flood went beyond officially recognized flood zones. Resident Michael Perius, basing his estimate on the debris line, said the water level at his property along Morita Reservoir went about 10 feet higher than where the floodway is marked on maps.

Perius' home was built high enough that it was not affected by the floodwater, but he said it is very possible that legal, permitted homes outside the designated floodway could have been washed away.

The county has no complaints that there were illegal structures or buildings without permits along Wailapa Stream, but will investigate, Miyake said.

"We are looking at what was permitted, where the housing was located," she said.

The Wailapa area where the flood disaster occurred is an agriculturally zoned region that was once part of Kilauea Sugar Co. The plantation closed more than 30 years ago, and much of the land has been carved up into agricultural subdivisions, many of which have been further divided through the condominium laws.

An Advertiser review of building permits issued for some of the parcels along Wailapa Stream reveals that most have at least one permitted single-family residence, and some also have a guesthouse. But many have numerous other structures with various titles such as yoga studio, lean-to and fruit shed.

Planners said such structures are not intended for residential use, but they concede that islandwide, things like a 500-square-foot "fruit shed" or other agricultural buildings are often converted into living quarters.

Wailapa area residents interviewed immediately after the flood said they were concerned about residential structures that had no permits at all, and might have been built too close to the stream.

The Wailapa streambed was densely forested before the Kaloko flood, which scoured the stream to bare dirt. Planners might have difficulty inspecting the site.

"If there are unpermitted people living by the stream, we don't know," Miyake said. "Unless a neighbor complains, we wouldn't have any way to know about it."

Reach Jan TenBruggencate at jant@honoluluadvertiser.com.