CRUDE flood mapping has a Warwick couple struggling to sell their property.

Despite having good soil and hillside views on the four hectare lot, David and Pam Hockings have failed to sell their Deuchar property, which borders Glengallan Creek, due to "incorrect” flood zoning.

Mrs Hockings said the couple had tried to sell for five years, but three buyers had been dissuaded by mapping, which placed the block of land in a flood plain.

"We didn't know zoning boundaries had changed until we got the first knock back in 2011,” she said.

"We were astounded because if we were under water, Warwick Town Hall would be under water.

"We had originally owned 20 acres, 10 of which weren't in the flood zone, and we sold that lot.

"But when the buyer found out the trouble we were having they offered us less than half price.

"It's got contours and good soil so it would be good for crops and the views would make it a lovely place to build a family home.

"Even though people can come out to the property and see clearly it's on a hill they're still guided by their solicitors' advice, as the zoning would make it difficult to get council approval to build.”

Southern Downs Regional Council director of engineering Peter See said the council had done mapping to the east of Kirkland Rd, within 1km of the Hockings' property.

He said cruder State Government maps provided the basis for zoning on the western side, a distinction made clear in maps on the council website.

"After the 2010-11 floods, the Queensland Reconstruction Authority was established and provided flood modelling through the whole of Queensland,” Mr See said.

"Council has done our own mapping in the area, which puts the high water mark at 250m above the QRA maps but unfortunately it ends at the front edge of their property.

"Due to the proximity of the property to our mapped zone, I was able to clarify the property is safe from flooding last September, but the challenge remains that anyone looking at the mapping online will assume it is flood-prone.

"Mapping gives us good controls for development and reliability in disaster management but it's costly.”

Mrs Hockings said buyers were still reluctant to make offers even with the council clarification.

"We're not really sure what to do,” she said.

"Even though we have the communication the property is out of a flood zone, people are still choosing to believe those records.

"We've shown our lawyers the information in the last week and we'd consider class action if there were other unhappy property owners.

"If council could update the information it could help but I think the damage it done.”