Long story short, for the past 4-5 months there's been a problem with the overflow on my house. I've spoken to the landlord 3-4 times about this, and he even had to gain emergency access to the property about a fortnight before I went to America as it had started to run. Since the problem started, I've tried to remember to turn off the stoptap under the stairs to cut off the water supply to my home while I'm not using it, and since the landlord had to come in to check the tank in the attic, I've only ever had the water on when I'm actively using it - ie to run the shower, or wash up. Each time I've spoken with the landlord, he's been like, "Fine, I'll arrange for a plumber to come around and check it out... this has never happened.

On monday, I received a letter from the waterboard. "We calculate you've used 300 cubic metres of water in this billing quarter, creating a bill of £1020.89." WHAT?
I called my landlord, and they've arranged a plumber to visit now, booked for monday. I've also called the waterboard, and they are coming out to check my meter reading - it's crazy stuff. The guy I spoke to at the waterboard agreed it's insane use for a single occupant. Most families don't use that much water in a year.
I've been through all my tenancy paperwork, and it looks like my landlord will be responsible for this due to the lack of action when I alerted him to the problem... I'm going to call citizens advice about it tomorrow to be certain. If that is the case, once the problem is fixed I'm going to write to my landlord with a copy of the statement the waterboard has sent me and ask him to meet the charges.

I normally pay £23 a month for my water service, and the account is usually in credit. The amended payments the waterboard has given me is well over £200... no chance I can afford that, and shouldn't have to considering it's not my fault.

I'll keep you posted...