Although the construction value increased on 1 January from €603 to €615 a square metre, “some properties still pay too much tax because the tax office does not automatically update the age of the properties or their location coefficient, which changes every three years”, DECO said.

“All these factors influence the municipal tax calculation, but the state only increases the value of the houses according to inflation”, it said.

Homeowners have to present a free request by 31 December each year to ensure the calculation is correct and not to pay too much the following year.

“A complete review of all the items in the calculation is only done when the house changes owner (by inheritance of acquisition) or when the owner asks the tax office to do so.

The consumer association advised homeowners to conduct a simulation on the internet page www.paguemenosimi.pt, where they can “confirm whether it is worthwhile updating the information about the property for the municipal tax calculation”.