Fit the rack / trivet insert into the bottom of the pressure cooker bowl. See notes below if you don't have one.
Cut your ham as needed to fit it into your pressure cooker and place it on the rack inside the pressure cooker.
Pour in the water, seal the lid, and set the pressure to cook on high for 6 minutes per pound (51 minutes for an 8 1/2-lb ham).
Release the pressure. Use the natural release method for 10-15 minutes (this will serve as the resting time for the ham to redistribute juices). Then switch to the quick release if desired to release remaining pressure.
Grab your meat thermometer. The internal temperature of a ham should reach 145ºF (simply for it to be heated through, since they come fully cooked anyway).
Notes
Expect an additional 30 minutes for the Instant Pot or other pressure cooker to come to high pressure if the ham is fridge cold. Add this time on to the total cook time when planning your meal.
If you don't have the trivet/rack insert, you can coil up some aluminum foil to lift the ham off of the bottom.
To GLAZE: Transfer the ham to a foil-lined baking sheet (this makes for easier clean-up). Brush the outside with my favourite glaze for ham recipe and broil until bubbly and caramelized.