Like many other municipalities, the state capital of Wiesbaden has a need for housing and therefore supports private initiatives for housing construction. However, the capacities of existing social infrastructure facilities may not be sufficient to accommodate all newly arrived children and young people. The necessary structural expansion of existing facilities or the construction of new facilities poses an enormous financial challenge for the state capital of Wiesbaden. The aim of the WiSoBoN guideline is therefore to allow the project sponsors to participate in the costs of provision to an appropriate extent.

In order not to overburden the project developers financially and also to leave them with an investment incentive for residential construction projects within the scope of this guideline, the financial burden on the project developers is limited. At least one third of the surplus generated by the planning from the development of the area (increase in market value, after deduction of other development costs) should remain with the developer or the landowner as an investment incentive. The increase in market value is calculated by comparing the property value before planning (initial value, depending on the actual condition of the property) and the market value after completion of planning (final value).

The extent to which the project developers are required to participate in the construction or expansion of existing social infrastructure facilities is determined in urban development contracts.

The developers are also obliged to provide affordable housing as part of the development of residential land by means of urban development contracts. The municipal council has passed separate resolutions on this. The resolution of 20 May 2021 (resolution no. 0220) states that for construction projects of 40 or more - additional - residential units, in which (residential) building rights are newly created under planning law, project developers or owners must realize at least 30 percent of the newly created residential units as subsidized housing (for low and middle incomes in accordance with the funding channels in order to achieve a balanced social mix). For companies with a (direct or indirect) majority municipal shareholding, the requirement of at least 40 percent subsidized housing units (for low and middle incomes in accordance with the funding channels in order to achieve a balanced social mix) applies to all new construction projects with 40 or more (additional) residential units. The distribution between low- and middle-income housing should be at a ratio of 2:1; deviations are possible in justified cases.

This regulation applies from the time the resolution is passed, unless the special regulations of the supplementary city council resolution no. 0706 of December 16, 2021 apply.