Soak your pecans in cold fresh water for at least 4 hours or overnight.
Drain and rinse the pecans.
Place pecans, 4 cups fresh filtered water, pinch of salt and maple syrup (optional) in a high-speed blender and blend continuously for 1-2 minutes, until the nuts are finely ground.
Pour into a jar and store in the refrigerator for up to 5 days, though it is better the fresher it is. Separation is normal in non-dairy milks, just shake it up before using it.
These nuts are soft so they do not need to be strained. If however your blender is not able to get the milk fine enough, or to a consistency you are happy with you can certainly strain it! Do this with a clean thin kitchen towel or a nut milk bag.