Yes, you are covered for damage caused by a water leak.
LV= buildings insurance
covers damage caused to your home by water leaking from any fixed tank, appliance or pipe. We also pay up to £5,000 (£10,000 on Home Plus) for the cost of removing and replacing any part of the structure of your home to find the source of a water leak so repairs can be carried out (trace and access).
Your belongings are covered too. LV= contents insurance covers damage caused to your personal items, such as sofas and carpets, by a leak from a fixed tank, appliance or pipe.
You can find full details of what's covered in your document of insurance.