IMI (Imposto Municipal sobre Imóveis) is the Portuguese municipal tax applied to properties introduced in the country in 2004 to replace the old municipal property tax called Contribuição Autárquica. Since that year, the tax has been subjected to some changes. The most recent is based on the coefficient of "location and relative operability".
From now on, that coefficient, which is an assessment parameter of the "quality and comfort coefficient", may be increased up to 20% or decreased up to 10%, against a current variation of 5%.
Here's an example: imagine a third-floor flat, whose apartments have the exact same area, but the last floor has a greater sun exposer and a better view compared to the others. Nowadays, these factors can influence the assessment of the property value by 5% (upwards or downwards). From now on, this variation can reach 20%, if positive, or 10%, if negative.
However, it is important to note that this change in the "quality and comfort coefficient" will only be applied to properties that will be subjected to a new assessment, since the AT (Autoridade Tributária, the Portuguese taxes and customs authority) won't make those changes reflect automatically on the current property value.
Probably, this aspect will be positive in cases where a request for an assessment would mean an increase of the taxable property value (or Valor Patrimonial Tributário in Portuguese), which consequently would increase the amount to be paid. On the other hand, considering the new rules, those who own a property and can benefit from the negative variation of 10% (on the example given above, properties on the ground floor), might be interested in asking for a new assessment of their property.
We remind that a request for a new assessment of your property to the AT is an optional choice. You can always ask for a new assessment every three years. Considering the new rules, everyone who owns a property must take into account essentially three factors:
1. the ageing coefficient, which focus on the age of the property (in principle, properties lose value as time passes; so there is a possibility for your IMI to decrease if you ask for a new assessment, something you can do every three years);
2. the location coefficient (which was revised in 2015, may influence your taxable property value, depending on the location of your house);
3. the quality and comfort coefficient (which in light of the new rules, it is important to consider its factor of "location and relative operability").
Now, what can come as a surprise is the fact that municipalities and other authorities can ask for new property assessments, even if their owners don't make that request. From now on, municipalities and parish councils can ask for new property assessments, which can increase the amount of IMI charged, which consequently mean an increase of their revenues.