The tax value of real estate periodically assessed by municipalities under the Real Estate Valuation Act (Wet WOZ). This law requires municipalities to periodically assess all real estate within their municipal boundaries and use the established WOZ value to determine the municipal real estate tax (ozb). Since January 1, 2009, the established WOZ value has been part of the system of basic registrations. The Basic Registration of Real Estate Valuation (Basisregistratie WOZ) enables the WOZ value established in the WOZ regulation to be used by all government organizations that have a legal regulation for that purpose. The WOZ value for a year is the value that a municipality provides to owners and users of properties at the beginning of the year. Because the municipality needs time to assess these properties, the value reference date is from the previous year. The value reference date (assessment reference date) is always one year earlier (t-1). For example, the WOZ value on January 1, 2022, is the actual value of the property on January 1, 2021. The Valuation Chamber oversees the implementation of the WOZ Act, including the quality of the assessments.