A New Forest resident complained to the authority in 2008 after council staff failed to edit data from a planning application before publication on its website.
Although data were eventually removed, the resident found that the council continued to publish applicants' personal details over a period of months.
Despite the introduction of self monitoring, the ICO established in July that they were still being published and contacted the council to tackle the issue.
The ICO is now satisfied that the necessary steps are being taken to prevent a breach reoccurring. "We will be monitoring other local authorities to scope compliance on a national level.
"Any found to have an unacceptable error rate may be subject to regulatory action," said enforcement group manager Sally-Anne Poole.