The Christchurch City Council is fast-tracking surveys of five properties it believes it has incorrectly assessed for their vulnerability to floods.
The South Brighton houses have all been rebuilt after earthquake damage.
But due to an error in calculating the threat posed by sea level rise, they haven't been built high enough to avoid future flooding.
Since it was alerted to the mistake last week, the council has been trying to find out how many homes are affected.
Today it has confirmed the mistake is confined to the five houses already identified.
It says none are at immediate risk of flooding.