thanks everyone for your replies!
A clarification:
I have now seen the letter from EPCOR, and it seems to be only regarding water (Epcor Water Services Inc. - EWSI).
According to the letter, the tenant is now more than 60 days in arrears. Upon 90 days' notice to the owner, EWSI can open a new account in the name of the owner. However, the owner is only responsible for water services from the date the account is opened, not for the tenant's arrears. (City of Edmonton Waterworks Bylaw No. 12585, Schedule 2, Paragraph 3.1(d))
So basically, if the tenant doesn't pay, in about 90 days they will open a new account in my name, and I will be responsible for the water bills from then on.
Out of curiosity, what is the average monthly water bill for a townhouse in Edmonton?