UPDATE 5/24/2018: I re-printed this because I did a test fit and saw the water was weeping out of the print walls. I also wanted to use black PLA so it would be less noticeable if/when the paint might fail over time.
I upped the shell thickness in Cura from default .8 to 2.0 and kept the infill the same. This seemed to do the trick. I added photos of the finished product.
Awesome scan by JanuszT! Hollowed out the head to allow water to pass through and added 3/4" female NPT pipe threads so I can attach it to a bulkhead that is used for a fountain in my pond. This is a scaled down version of the original scan to fit my needs.
I need to paint and install so it has not been tested but it screws on nicely to a 3/4" pipe. I will add photos when completed.
I used the bushing made by wbhinton for the 3/4" NPT threads. https://www.thingiverse.com/thing:1006420
Printed perfectly with no supports. PLA using Cura