A customer that wishes to switch supplier to a water supply licensee must satisfy each of the following three requirements:

• The customer's premises are not household premises;
• The annual consumption of water on the premises must not be less than 50 megalitres at the time the customer wishes to switch; and
• The premises are not being supplied by another licensee, but may be supplied by a licensee and one or more appointed water companies.

In all cases, it is the licensee rather than the water company that must make sure that the premises of a potential customer are eligible to switch supplier. Licensees can only supply customers at individual eligible premises. Each of the premises supplied must be eligible by itself. A customer cannot aggregate consumption at more than one set of premises in order to be eligible, although some groups of properties may constitute a single set of premises in certain circumstances. There will be a single set of premises in the following circumstances:

• The premises are located within a single boundary and a single customer occupies the premises and is liable for water bills for those premises;
• The premises consist of 'co-located' buildings (or land) which have adjoining boundaries or which are separated only by transport infrastructure, and a single customer occupies the premises and is liable for the water bills for those premises; or
• The premises consist of a single building or co-located, separately occupied buildings, with the following characteristics:
  1. (i) they have a common landlord or managing agent,
  2. (ii) they have adjoining boundaries or are separated only by transport infrastructure,
  3. (iii) they are served by a self-contained common water supply system that does not belong to the water company, and
  4. (iv) a single customer is liable for water bills in respect of the totality of the premises.

Premises that are considered to be a single set of premises must also satisfy the requirement that they are not household premises. Our guidance  sets out a list of what we consider to be household and non-household premises for the purposes of water supply licensing. Having considered this list, a customer or licensee might find that a single set of premises is made up of household and non-household elements, for example health workers' accommodation on a hospital site. For the purposes of water supply licensing, household premises are those in which, or in any part of which, a person has their home and where the principal use of the premises is as a home. We consider that the principal use of 'mixed-use' premises will not be as a home where both of the following apply:

• The household part of the premises is dependent in some way upon the non-household part. For example, a university hall of residence would not exist in the absence of the university itself.
• The bulk of the water consumed is for non-household use. We consider that 'bulk' means more than 50%.

The criteria above should only be applied where there are mixed-use premises and the principal use of those premises is in question. As mentioned above, a customer wishing to switch supplier must be consuming at least 50 megalitres of water a year. Our guidance explores the issues associated with assessing whether this criteria has been met, including methods for assessing consumption of both metered and unmetered customers, potable and non-potable supplies and private supplies. This is only intended to be a summary of the issues regarding the eligibility of customers to switch supplier. Our guidance provides more detail about how eligibility should be assessed.