According to Section 196 of the German Building Code, standard land values are average location values for land. They are determined on the basis of the purchase price collection and decided upon every two years by the Mainz City Property Values Expert Committee after extensive consultation in a closed meeting.
Standard land values indicate the average land value for several properties in an area (standard land value zone) that are essentially identical in terms of use and value. They are determined taking into account the different stages of development and, by definition, refer to fully developed properties in an undeveloped state. They do not include any value for vegetation. They also indicate the land value of a developed property that corresponds to the standard land value property in terms of the type and extent of building use. 

The standard land value maps are available for inspection at the office of the expert committee. The office is located in the Citadel, Building C, Rooms 205-208, and is open Monday to Friday from 9 a.m. to 12 p.m. and from 2 p.m. to 3:30 p.m. (Friday 9 a.m. to 1 p.m.).

The standard land values can also be viewed free of charge on the Internet in the Geographic Information System of the City of Mainz.
In addition to the current standard land values, you will also find the standard land values for the reference dates 2014, 2016, 2018, 2020, and 2022.

Written information on standard land values from the office is subject to a fee.

Standard land values in the geographic information system

Instructions for use: First, select the desired map section using the street search and, if necessary, the house number or zoom function. Then activate the display of standard land values via the topic selection. Next, activate the "i" button above the map. Click on the desired area to display the description of the standard property for the selected standard value zone.

Note: The standard land values are visible from a scale of 1:10,000.