Is there a certain amount of water you're supposed to drink or hydration level to get an accurate bp reading?

Bp and hydration: In healthy people, blood pressure is kept stable by the kidneys and does not change much unless one is VERY dehydrated, so much so that urine production is decreased. If one is dehydrated from in ability to drink fluid or excessive diarrhea, the blood pressure may be lower and difficult to elevate by the kidneys. It is always good to keep well hydrated, especially if you take bp meds

Normal: if no bleeding or dehydration, no change in usual liquid consumption is required to get an accurate blood pressure