Any city wishing to become a member in good standing of the OWHC (as a member or observer member) must pay an annual membership fee, in which case it will be entitled to the following services offered to each category of membership:

Annual Membership Fees

OWHC membership fees for cities are determined as follows:

The variable portion is determined by the formula [GNI /capita x population/1 000 000]

GNI/capita data are determined by the World Bank. They consist of comparable data between all countries and are determined by World Bank experts. Population data are updated based on the online database CityPopulation.de which provides statistics for the main cities and agglomerations worldwide.

The fixed portion is the same for all cities of the same category.

These categories are also based on the GNI /capita and are numbered from 1 to 4 in ascending order of national incomes (see table below). Accordingly, a Category 4 city will have a higher fixed income portion than a Category 1 city. These categories are those identified by the World Bank.