When drawing up or amending land use and development plans, municipalities are required by the Building Code to involve their neighboring municipalities. These can examine possible effects and contribute their concerns to the planning considerations.

The Office for Urban Research and Sustainable Urban Development coordinates the state capital of Mainz's response to neighboring municipalities.

The Neighborhood Committee is a joint committee of the Mainz City Council and the Mainz-Bingen District Council. The committee meets at irregular intervals to discuss common issues (e.g., transportation, housing construction) and makes recommendations to the city council and district council.

The Office for Urban Research and Sustainable Urban Development manages the affairs of the state capital Mainz in the Mainz-Mainz-Bingen District Neighborhood Committee.

Planning approval is a special administrative procedure that examines the admissibility of spatially significant projects and infrastructure measures that affect a wide range of public and private interests due to their spatial dimensions and impact. These include, for example, the expansion and construction of power lines. Planning approval procedures are carried out by the relevant state and federal authorities. The municipalities that may be affected by the impacts are involved and consulted during the course of the procedure.

The Office for Urban Research and Sustainable Urban Development coordinates the statements within the city of Mainz for participation and hearings in the context of planning approval procedures in the urban-rural context. In addition, it organizes the public display of documents for inspection by citizens and provides information on procedures that affect the area of the state capital Mainz or in which the state capital is involved.

Regional planning procedures are carried out by the higher state planning authority for projects with significant regional implications. These include, for example, the construction or expansion of major transport routes or large-scale construction projects. Such procedures are preliminary review and coordination procedures. They are carried out at a relatively early stage of planning in order to identify conflicts in good time and, if necessary, to work towards a more optimal project or location alternative. The municipalities that may be affected by the impacts are involved and consulted during the course of the procedure.

The Office for Urban Research and Sustainable Urban Development coordinates the statements within the city of Mainz from the municipal departments responsible for participation and consultation in the context of regional planning procedures. In addition, it organizes the public display of documents for inspection by citizens and provides information on regional planning procedures that affect the area of the state capital Mainz or in which the state capital is involved. 

On the Rheinhessen side, the Regional Day was launched in 2019 to jointly address regionally significant topics such as housing, mobility, health, and digitization. The districts of Mainz-Bingen and Alzey-Worms as well as the cities of Worms and Mainz are represented.

The Office for Urban Research and Sustainable Urban Development alternates between managing the Regional Day and coordinating tasks.

Regional planning is the interface between local planning by municipalities and higher-level state planning. Here, the objectives and principles of state planning for individual regions are specified and coordinated with municipal urban land-use planning (land-use and development planning). Rhineland-Palatinate is divided into five planning regions. Mainz belongs to the Rheinhessen-Nahe planning association.

The Office for Urban Research and Sustainable Urban Development coordinates the statements within the city of Mainz on the regional spatial development plan or other regional plans, such as the regional commercial space plan.

The City Committee is a joint committee of the Mainz City Council and the Wiesbaden City Council. The committee meets at irregular intervals to discuss common issues (e.g., in the areas of mobility or real estate) and makes recommendations to the city council or city assembly.

The Office for Urban Research and Sustainable Urban Development conducts business on behalf of the state capital of Mainz in the Mainz-Wiesbaden City Committee.