Add the rolled oats and 3 cups of water to a
blender. If you're adding salt, sweetener or vanilla, add those as well. Blend on medium to high speed for 30-60 seconds until smooth and creamy. I blend it for 20-30 seconds in my Vitamix. See how you like the consistency with 3 cups water and add more to adjust. I use 3.5 cups water but feel free to increase that to 4.