For my poisonous office plants I needed a small watering can. I have seen some interesting designs on thingiverse in the past but I do not find them anymore. So I made something similar. It will hold about 0.5 - 0.75 l water. This thing prints nicely without support. To be sure that it is waterproof, I recommend 0.1mm layer height, 3 walls (1.2mm) and 100% infill.