It depends on how and why it happened. If the leak was caused by an unexpected event, such as damage to an otherwise well-maintained roof during a storm or a fire, you should be able to make a claim on your buildings insurance.
If the leak caused damage elsewhere, fixtures and fittings may also be covered by your buildings insurance. You would need to claim on your contents insurance for water damage to your belongings, such as spoiled carpets and curtains.
If the leak happened due to lack of maintenance or wear and tear, perhaps through not clearing gutters or not replacing lost tiles – even if a storm, for example, made it much worse – your insurer may not pay out. To help avoid this, carry out preventative maintenance on your home, and fix problems when they happen – and before they get worse.