Pursuant to Art. 6m, paragraph 2 of the Act of 13 September 1996 on maintaining cleanliness and order in municipalities (Journal of Laws of 1996, No. 153, item 1595, as amended), in the case of data which are the basis for determining the amount of municipal waste management fee due or the amount of municipal waste arising from the given property set out in the declaration, the owner of the property is obliged to submit a new declaration by the 10th day of the month following the month in which the change occurred. The fee in the changed amount shall be paid for the month in which the change occurred.
In the case of failure to submit the declaration on the amount of municipal waste management fee or reasonable doubts regarding the data contained in the declaration, pursuant to Article 6o paragraph 1 of the Act on Municipal Waste Management, the head of the commune, the mayor or the president of the city shall determine, by way of a decision, the amount of municipal waste management fee, taking into consideration the available data relevant to the method selected by the communal council, and in case of lack of such data - reasonable estimates, including in case of properties where no residents reside, the average amount of municipal waste generated in similar properties.