This template gives the water area in km2 of each municipality as text output based on the CBS code or name of municipality. It is used as follows:

{{Dutch municipality water area|XX}}

with XX the CBS code, for example: {{Dutch municipality water area|1680}} → २.७८
or the name, for example: {{Dutch municipality water area|Aa en Hunze}} → २.७८
Each municipality has a code assigned by CBS, see List of municipalities of the Netherlands for an overview.

The data in this template is calculated as the difference of the total and land area obtained from their respective data templates.