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You are here: Home > Developers > Local engineers


Sewerage and sewage treatment

We offer a range of services for members of the public, builders, local authorities and housing developers. We provide on line information and downloadable application forms for your water supply and drainage needs.

Adoption of new sewers

We promote the use of a Section 104 Agreement (under the Water Industry Act 1991) for the adoption of sewers that are to be constructed as part of new developments. Sewers must be constructed in accordance with the current edition of the publication Sewers for Adoption which is available from the Water Research Council. It should be noted that a new edition of Sewers for Adoption is now in force. We maintain the sewers as public following adoption.

Fees and costs are at national rates as set out in the publication above and are based on our estimate of the whole cost of the works being offered for adoption.

Inspection fees are set at 2.5% which covers technical assessment and site inspection (a minimum of £500) and legal agreement preparation of £325.

You should discuss your proposals beforehand with our local development engineer.

A preliminary application form for the adoption of new sewers may be found here and a formal application form with example gravity sewer schedule here.

Advice Note 16 is the Proposed new Mandatory Build Standard and Sewers for Adoption. Defra, on behalf of the Government, is implementing changes whereby it will be mandatory for new foul sewers and lateral drains (between the sewer and the serviced property boundary) to be adopted to public status by the sewerage undertaker.

The proposed date for the transfer of private sewers is currently 1 October 2011. It should be noted, however, that this timeframe is subject to change if the legislation is delayed on its progress through Parliament.

Advice Note 4 deals with issues relating to site inspections and included details of our site inspection areas and contact telephone numbers. This information is also applicable for buildovers and diversions.

  Advice Note 6 Where PE rising mains are to be installed as part of an adoption, this note provides useful information to the groundworker in relation to installation and joint arrangements acceptable to us.

Advice Note 7 A copy of the site investigation report should form part of any adoption application in order to determine the existence of any contamination. This document details the information required in the report. The type and level of contamination may affect the choice of materials and installation method.

Advice Note 8 This note lists the requirements and standards for CCTV surveys being submitted to us for adoptions and diversions. It includes a list of CCTV companies which currently work directly for us. 

Adoption of sewerage pumping stations 

Under the new edition of sewers for adoption each sewerage undertaker has its own pumping station addendum. Our addendum can be found here.

We also control and maintain pumping stations by telemetry, as indicated in the pumping station addendum. Such a system must be installed by us at the developers' cost when a pumping station is being offered for adoption. An application form for the installation of the system can be found here.

Advice Note 1 sets out the information we require to be included within the Health and Safety/Site File when a pumping station is included in the Section 104 Adoption Agreement.

Advice Note 2 gives the developer advice on septicity. When a pumping station forms part of an adoption application concern is raised regarding the prevention and control of septicity.

Advice Note 3 is a list of the items and areas which we will check as part of any Pre-Maintenance Inspection. The developer may wish to use the list as part of their site supervision checks prior to requesting a formal inspection by us. The use of the form may save the developer time and money as any failure during the formal inspection may result in charges being made for any further inspection and delay adoption.

Advice note 11 provides further information on the adoption of sewers, rising mains and pumping stations as covered under the new edition of 'sewers for adoption'.

Adoption of sewage treatment works

We can consider adopting private sewage treatment works. This type of works is often referred to as a ‘package plant’. 

UK Water Industry Research has published a national standard and adoption procedure. Wastewater Treatment Works for Adoption, UKWIR reference 13/RG/05/38, ISBN number 1-84057-696-0 is available from

You should discuss your proposals with our local developer services engineers using the contact details here.

Adoption of existing sewers

We can adopt existing sewers under Section 102 arrangements. The applicant(s) must provide details to prove that the sewer(s) have been designed and constructed to an adoptable standard. Before the sewers are adopted the applicant will need to pay all inspection fees and any remedial costs incurred. Once the sewers have been adopted, we maintain them as public sewers.

Fees and costs are based on the size of the application and the amount of information and work required processing it. As a guide, an initial deposit of £250 for a single sewer or £2,500 for a full estate is requested when an application is received. You should discuss your proposals beforehand with our local development engineer. A guide and application form for the adoption of existing private sewerage systems can be found here.

Diversion of existing sewers

If there are existing sewers crossing a new development site and the layout of the site cannot be designed to avoid them, the sewers must be diverted. The applicant can propose a scheme and ask us to consider whether a diversion is possible. Any diversionary works are done at the cost of the applicant.

When a scheme is agreed we will complete the works on a fully rechargeable basis and recover all costs from the applicant. In some cases we will allow a suitably qualified applicant to complete the work themselves under a legal agreement with us. In this case we will require a deposited sum as a surety against poor workmanship etc. This sum is equivalent to 10% of the cost of the scheme or £5,000 minimum.

Inspection fees are set at 2.5% of the cost of the works based on our standard contract costs. Technical administration costs (a minimum of £500) and legal agreement preparation of between £150 and £325 are in addition depending upon the type of agreement.

You should discuss your proposals beforehand with our local development engineer.

An application form can be found here

Building over/near to a public sewer

If you are planning an extension to an existing property, building a garage or a conservatory etc, there may be a public sewer in the way. If you want to build over or near to that sewer, you must agree protection measures for the sewer with us.

  • Guidance notes can be found here.
  • An application form can be found here.
  • Details of our fees can be found here.

You should discuss your proposals with our sewer protection team on 01225 526333 or email us.

Requisition of new sewers or laterals for domestic purposes

Where there is insufficient capacity in our system to accommodate your discharge we may require you to pay for any necessary improvements. It is important that you contact us at the earliest possible stage as major works may be required to accommodate your development.

If you have a new development site with no access to a public sewer because land owned by a third party is in the way, we can lay a sewer(s) to serve your site. We can negotiate land entry, easements and compensation for crossing the land.

In the case of sewers we are required to offer various methods of payment. Please contact the local development engineer for details.

In the case of a lateral drain, payment in full becomes due after we have laid the drain. For sewers and lateral drains, we normally require financial security, usually in the form of a cash deposit.

If you wish to connect non domestic flows to our sewerage system, you will need a trade effluent discharge consent. You will need to submit a trade effluent notice giving details of the proposed flows. We may impose conditions to safeguard our sewers and sewage treatment works.

You should discuss your proposals with our local development engineer. An application form can be found here.

Advice note 14 provides information on the possible £1 contract option to a formal requisition procedure.


First time sewerage schemes

You can ask Wessex Water to consider providing a new sewerage system in an area lacking public mains drainage. Applications are accepted from district councils, parish councils, or groups of householders. We will investigate if a scheme is viable, and if it is confirm when it may proceed. If a scheme is not viable, we can advise you on your alternatives.

You should have an initial discussion with our local Developer Services engineers using the contact details here.

An information leaflet can be found here.

A leaflet answering questions for when a scheme goes ahead can be found here.

Infrastructure charges

All new developments and connections place additional demands on our existing systems. Infrastructure charges were introduced by the government as a way of ensuring that all new developments and new connections make a contribution to the upkeep of public water mains and sewers. The infrastructure charge you pay depends on the type of development, although there is a standard charge for each house, flat or similarly occupied premises with its own standard size domestic water supply connection. It should be noted that the infrastructure charge is separate to any charges for obtaining a new connection to our water supply or sewerage system.

Connections can be direct to our systems or indirect via private mains, drains or sewers. The amount payable depends on the type of development and whether a supply and/or sewer connection is required. In the case of multi-occupation developments, ie, flat, offices etc, the charges will be based on the number of water taps and water using appliances.

For 25mm domestic water supply connections the standard amounts are:

Water £347
Sewerage £347

Infrastructure charges are zero rated for VAT.

All other properties are charged an amount calculated using the relevant multiplier, (RM). The RM is based on the number of taps and water fittings in the property. Each fitting is given a loading unit based on the amount of water it uses.

Further information you can email us.

Connecting to a public sewer

If you want to make a new foul or surface water connection from your new property or extension to a public sewer, you need to apply beforehand.

To discuss your proposals with our sewer connection team, call us on 01225 526333 or email

Asset information

If you wish to obtain sewer records information, please call our mapping department on 01225 526422, fax on 01225 528262 or email us. A charge will be made for this service. Alternatively, public sewer records can be viewed at local district council offices.


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