Immovable property tax is the most common form used in property taxation. Its potential inauguration into the Croatian tax system is connected to a series of questions that require a thorough analysis. Property taxes are mostly levied on a local level, and their aim is to make the residents contribute to the financing of the public utilities they use. This model of financing local public services contributes to the increase in the value of real estates and provides for a stable and reliable source of financing to local units. Based on the international comparative review of taxable items and the method of determining the tax base and tax rates by EU member states, it is clear that real estate taxes in most EU member states represent a source of income for local budgets that they independently determine. In Croatia, there is still no form of property tax where the value of the property represents the tax base, so the question is what is the efficiency and fairness of the existing system of financing public services. Property taxation in Croatia is carried out through various taxes and user fees, which is the basis for calculating the surface of the real estate. Such tax discrimination is one of the main disadvantages of the user model and provides an argument for incorporating immovable property tax into the model of financing local units. With the abolition of communal fees (purposeful givings used to finance public services such as drainage of atmospheric waters, maintenance of public areas and unclassified roads, and cleanliness of roads and parks) and other user fees associated with real estate and replacement of a unique immovable property tax (non-purpose tax for financing all local administration and self-government activities) would lead to more efficient financing of local self-government units. This paper proposes a new model of real estate valuation for the purpose of determining the tax base according to the cost method. Local self-government units have access to data for the calculation of utility charges and possess a real estate database, so it would be logical for local self-governments to determine and charge immovable property taxes, and for the income from this tax to belong entirely to local self-governments. The existing data relevant for determining the obligation to pay utility charges would also partake in a new model for the calculation of immovable property taxes as an upgrade platform for the existing model.