We use a Keurig machine without a water storage and needed something to measure the water that didn't look like an everyday measuring cup.
This will hold 8oz. to the horizontal line in the model which is the same as the fill line in our machine.
This is a solid model so you can adjust your slicer to the proper perimeter thickness to print water tight. Simply use 0 infill and 0 top layers.
If you use more than say 4 perimeters, you may want to scale a percent to compensate the volume.
General FDM printing info
As with any FDM 3D prints, it is not advisable to use for storage or liquids other than water as there is a chance bacterial can grow between un-fused layer lines