As far as I am aware precooking raw beef has nothing to do with food safety. If you are stewing it for hours, there isn't going to be much that could survive those temperatures.

Pre-cooking or browning the meat in a stew is all about flavor. It is all about the Maillard reaction (the browning of the sugars in the beef) which brings out a lot of flavor.

so... there is a good reason to brown the meat, but you don't have to. Since you already have a pot, why not brown the meat first? If you are concerned with the mess of the brown bits at the bottom of the pot (fond.... so much flavor), when you add the water, it should deglaze nicely.