I have a bowl of three hyacinths in my living room in full bloom. The thing is that I don't know whether or not to give them any water as I wonder if they get all the moisture they need from their bulbs. Can anyone advise please?
Yes, keep them watered.
An alternative method of growing them indoors is to grow them in a hyacinth vase which requires the roots to be submerged in water, so yes they can cope with plenty of watering.
if you do the bulb in a hyacinth vase thing, be careful. Modern bulbs have been bred to have bigger heavier heads than the bulbs that the vases were designed for and there is a horribly good chance that the bulb will become top heavy, overbalance and smash the vase. If you want to do bulbs in bulb vases, buy the kind of hyacinth that is sold in bulk for planting outside. the bulbs and the flowers are smaller, you get the same lovely scent with less risk of an accident.