Separate water meter for garden to save on wastewater charges?

We had to water a lot in the first garden year, we maintain 4.5 ares and the excess consumption was at least 40 cubic meters. In the district of BB in our home municipality, I was able to calculate the garden water meter below zero. It is not always economically sensible. However, I also know of municipalities where, for example, pool fillings are easily deducted.

Best regards Gabriele