Hi to all I designed a "round ball" type of water tower, common to a lot of towns. It is in n scale, but scalable. I added a vent hole in the bottom to drain out any trapped resin. If you lay it down for the build, you may need to add additional weep holes. Also, you may need supports depending on your printer.
https://www.tinkercad.com/things/cOKwvPBFVpJ-round-city-water-tower