Availability of hydrological reports for heat pump

Before the installation of a water-to-water heat pump, the quality and location of the groundwater are checked with the help of a hydrological report. Can I find out where such reports have already been made near my property in order to save myself (the cost of) another report? Of course, I would gladly reimburse the "report provider" for part of their costs.

I think the Lower Water Authority of your district should know something like that.

For Lower Saxony, there is a "drilling point register." This also includes drillings for heat pumps (I just validated that). In some cases, the drilling columns are also available.

No idea which federal state you are looking at.