New Appointments & Variations (NAVs)


What is a NAV?


New Appointments & Variations (NAVs) are companies that provide water and wastewater services to customers by acquiring the local licensing and replacing the incumbent company for a specific area.


NAVs can compete with incumbents (the water and/or sewerage provider that holds the existing monopoly to provide services to premises in its supply area) to supply infrastructure to development sites (such as new build or retail developments) that aren’t served by the current incumbent.

Are there different types of NAVs?


NAVs can take on two broad forms:


Full NAV 


A Full NAV provides a complete “end-to-end” service. On the water side, this incorporates obtaining a water source, treatment, distribution and retailing. On the wastewater side, this incorporates collection, treatment and sludge treatment including disposal.


Bulk Supply NAV


A Bulk Supply NAV provides its own onsite infrastructure, but relies on a bulk supply of water (or a bulk discharge of wastewater) from the local incumbent’s network. The NAV still serves end-customers, but the NAV pays the incumbent for bulk services. 


Some NAVs may use a Bulk Supply for one service (e.g. water) but have their own resources for the other services. NAVs have the same duties and responsibilities as the statutory water company.


When companies apply for a licence, Ofwat check that the applicant has the ability and resources to meet its legal duties and responsibilities. 


The Drinking Water Inspectorate and Environment Agency also separately check the suitability of the applicant. 

When can a NAV be granted? 


A NAV can be granted in three different scenarios:


1. If the premises of one or more customers is supplied with at least 50 megalitres of water per year. The same applies for water recycling services.


2. If none of the premises within the area are currently served by an appointed company. This includes areas which are supplied by private, unregulated supplies. This applies for water and water recycling services.


3. If the existing appointed company consents to the transfer of that area.

Apply to become a NAV 


For NAVs looking to apply for a Bulk Supply for a particular site, we require a Preliminary Mains Enquiry Form to be completed found here: Bristol Water Preliminary Mains Enquiry Form.


In addition to completing the above form also require the following:


  • Site Location Plan
  • Build Profile with property numbers/demand

On receipt of the above Bristol Water will provide the following:


  • Point of Connection(s) (POC)
  • Cost of providing Bulk Supply Infrastructure
  • Draft Bulk Supply Agreement (General and Specific)
  • Minimum and Maximum pressures at POC
  • Site Served/Unserved letter
  • Total Infrastructure Charges payable
  • Total Income Offset Payable
  • Confirmation of reinforcement/diversions required

For any queries please contact Tim St John – Senior Project Manager – Development Services:

NAV resources


Contact us about developments

All pre-development enquiries and mains applications from developers will be dealt with by our Developer Interface Team who will arrange for any required mains to be designed and priced, terms to be sent and the mains to be installed.

Sharon Ranahan – Developer Interface Manager

All enquiries from Self-Lay organisations and applications will be dealt with by our Development Services team who will produce or check the design of any required mains. They will send out agreements and deal with the payments for any non-contestable work. They will also deal with the asset value payments at the end of the job.

Tim St John – Head of Development Services

To discuss issues encountered onsite once mainlaying has begun, including changes to the design, you should speak to one of our Network Site Agent. You will be notified of the person responsible for your site before work commences. They will inspect the work as the installation progresses, go through your as-laid plans with you, arrange bacteriological testing and attend the pre-start meeting. Weekly whereabouts should be sent to our Network Site Agent.

Nick Parr – Development Services Operations Manager

You should contact our New Supplies team about service connection issues. They will inspect the supply pipes before connection, authorise the connection and deal with the invoices and payments connected with the services.

Lynn Hawkins – New Supplies Manager

Please address correspondence to the relevant department at:

Bristol Water
Bridgwater Road
BS13 7AT