The owners of the two lakh-odd flats on civic “colony land” across the city will finally be brought into the house tax net.

Most of the owners have been enjoying a “tax holiday” ever since the buildings came up, as the structures are all unauthorised, despite having water, electricity and drainage lines.

PricewaterhouseCoopers (PwC) has suggested a roadmap for bringing the buildings within the tax purview. Sources said the report will be formally accepted at a meeting convened by the civic revenue department on April 9.

Municipal commissioner Alapan Bandyopadhyay and the controlling officers of eight civic departments will attend the meeting. Tata Consultancy Services and KPMG, too, have been invited.

The Calcutta Municipal Corporation had hired PwC following the Gariahat treasury defalcation case, to suggest modifications of the tax and audit systems.

The consultants have suggested withdrawal of two circulars issued by the civic commissioner — circular 20, of 1995, empowers the colony committees, which are nominated political bodies, to sanction these buildings, while circular 3, of 1998-99, states that the property tax of the apartments will remain unchanged even after assessment.

According to revenue department officials, if an apartment is charged Rs 1,000 as annual property tax, the civic coffers will be richer by at least Rs 20 crore.

Around 50,000 plots, each measuring three cottahs, are referred to as colony or patta land, as the government had allotted them to families from erstwhile East Pakistan.

Highrises have come up illegally on at least 40,000 of the plots, though in the civic records, only thatched houses exist on them. Efforts at assessing the buildings often resulted in backlash from the residents.