In many 'commercial' or 'new ways' of conducting intermittent fasts people will continue to drink water, and will only abstain from food and other beverages for the fasting period.
From your question I assume that you are not drinking water during your fasting period (presumably sunrise to sunset from your notes). In this case, I think it is best to listen to your body. Simply put, if you're thirsty during your non-fasting hours, then drink. If you're not thirsty, then don't drink.
The body is such a complex system that will always fight to stay in a natural state of balance. If there is too much water, you will simply pee it out and your urine will be really light to almost colourless. If you don't drink enough your urine will be really dark in colour and really small in quantity. If you're finding that shortly after your fast begins each day your pee is small and concentrated, then you're probably not drinking enough during the 'eating' phase of your fast. If you're peeing out heaps of clear liquid, you can rest assured that you're getting enough (NB: it's normal for your pee to be dark and concentrated later on in the day if you've been fasting for 8+ hours).
Some tips to avoid getting dehydrated:
- avoid caffeine and caffeinated drinks during your non-fasting period of the day
- avoid heavy exercise or any activity that will get you sweating bucketloads, particularly in the sun!
- check any medication you are taking with your doctor e.g. diuretics don't go well with fasting, but this doesn't mean you should stop taking them : you *must* consult with your doctor
- avoid salty foods and salt tablets
- avoid alcohol