Requisition Public Sewer

Application to Requisition a Public Sewer

If your site has no means of drainage to an existing public sewer due to third-party land, Services First Limited  can provide advice to assist you acquire  both a foul and surface water public sewer to serve your site via a public sewer requisition under Section 98 of the Water Industry Act 1991. Sewer requisitions do not include the individual connections to the sewer itself. Each property included in the requisition will need to make a separate application to connect to the public sewer.

Call Services First Limited For Further Information on

07904 882 792

Information required by TWUL to undertake requisition of a public sewer

The applicant’s full name, contact number and email address.

The location of where the sewer is to be constructed.

A drawing showing the location of the site where the sewer is to be constructed in PDF format.

A document showing the site drainage layout in PDF format.

Details of all properties to be connected to the sewer and details of any third-party land owners.

A document showing the soils and borehole information.

Statutory undertaker’s information.

Valid planning consent for the site.

Valid credit or debit card to pay the £1,000 deposit.

Guidance Notes From TWUL

Requisitioning Public Sewers

Under Section 98 of the Water Industry Act 1991 (the Act) any person entitled under the Act may apply to requisition a sewer to serve premises for domestic drainage purposes. Sewer requisitions will not include connections to serve individual premises to the sewer.

On site sewers should be constructed by the customer. If the sewers are intended for adoption a separate application form is available on request from our contact centre on the above number.


The Requisitioner will be required to provide the following information with their application:

The number of domestic dwellings, or for non-domestic developments the anticipated water consumption.

The anticipated rate of occupation of dwellings (not the rate of completions).

The site plan.

The details of arrangements for drainage within the site.

A valid planning consent.

A cheque for £1000, which will be refunded if the application is rejected by Thames Water.


An Initial Payment of £1000 (as submitted with the application) to cover the cost of preliminary investigations and the production of preliminary budget estimate. The budget estimate will identify the preferred route, scope of works, principle quantities and a provisional programme. The estimate produced is for indicative purposes only and will

be constructed using standard budget estimate rates in the absence of detailed site, soil, utility and design information. This payment will not be refunded if you choose not to proceed with the scheme.

An Interim Payment. This will be 10% of the budget estimate (a minimum of £10,000) and will allow the scheme to be progressed through to the final design stage.

Further payments may be required during the design phase, depending on the works required to complete design. At the end of this stage the applicant will be sent the requisition offer letter outlining the payment options available to enable the scheme to be delivered. If the scheme is abandoned at any time during the design stage, a refund will be made of any money that remains after the costs incurred by Thames Water have been deducted.

Requisition Payment  You may choose one of the following three payment options. We are required to offer you the second two options under the provisions of the Water Industry Act 1991 (“the Act”). However, some customers may prefer to choose the first option, which is a commercial arrangement  not covered by the Act. The requisition payment takes into account money paid at the initial and interim payment stages. In some cases the commercial option may not be offered.

Option 1 – Payment by commercial commuted sum

As stated above, this option is not covered by the Act and is a matter for agreement  between Thames Water and the customer.

The commercial commuted sum is assessed as a percentage of the scheme cost after taking into account the anticipated annual income from properties to be connected to the sewers.

The sum must be paid in advance of any works commencing, after which no further payment will be requested from you except where variations to the scheme are made at your request subsequent to works commencing. Any increase in costs resulting from such variations will be re-charged at full cost.

Subject to this, we will not re-visit the cost of the works after completion or make any subsequent adjustments to the commercial commuted sum.

Please note that the commercial commuted sum method of payment outlined above is offered at Thames Water’s discretion. There may be instances when the commercial commuted sum method cannot be offered and the statutory payment schemes outlined below will be followed.

Option 2 – Payment by statutory commuted sum

The Act permits customers to pay for sewers by a discounted aggregate deficit method, which is a statutory commuted sum.

The Act states that this sum is an amount equal to the sum of the estimated “relevant deficits” for each of the twelve years following the provision of the sewer. The “relevant deficit” is the amount (if any) by which the sewerage charges payable for the use of the sewer during that year exceed the annual borrowing costs of a hypothetical loan (at a rate of interest prescribed by Ofwat) of the amount required for the provision of the sewers.

Our estimate of the statutory commuted sum must be paid in advance of any works commencing. Alternatively, we will accept a bond for the relevant amount from an acceptable bondsman. We will provide on request the wording we require to be used in such a bond.

On completion of construction, actual project outturn costs will be calculated and if different to our initial assessment of costs, the commuted sum will be recalculated. Calculation of outturn costs can only take place following agreement and settlement of costs with our delivering contractor. Please note, this may be some time after the completion of works on site. Where the recalculated sum is lower than the estimate, we will refund the difference. However, where it is higher, you will be required to pay the extra amount.

Please note that any variations to the scheme resulting from your requirement will be charged at full cost.

The calculation of the estimate is based on the rate of occupation profile provided in your application. Consequently, any variations to that programme will affect the final figure.

Interest will accumulate on deposits made at a rate prescribed by Ofwat for each three month period that the deposit is held by Thames Water.

Option 3 – Undertaking with security

You may give an undertaking under Section 99 of the Act to pay the “relevant deficit” (as defined above) for each year of a twelve year period following provision of the sewer.

We will require security for these annual payments. In most cases the security will be no more than the estimated statutory commuted sum, although there may be cases where we consider that the risk justifies  a greater level of security. The security can be paid by way of a deposit of money and this will accumulate interest at a prescribed rate. Alternatively, we will accept a bond for the relevant amount from an acceptable bondsman. We will provide on request the wording we require to be used in such a bond.

Project Design

The exact nature and extent of works required to provide off-site sewerage is decided by Thames Water. If the works are to connect to existing public sewers, the point, mode and manner of connection are determined, taking into account existing and proposed flows. In some cases, the nearest reasonable point of connection will not be the nearest public sewer. It may be possible by agreement, to provide a nearer point of connection and incorporate the necessary sewerage improvements in the locality in the requisitioned scheme.

The works may be designed to cater for flows not arising from the requisitioner’s development. The costs attribute to those additional works will be borne by Thames Water.

Contract and Final Contribution

Requisition projects are normally procured through Thames Water’s Framework Agreement with major civil engineering contractors. The Framework Agreement was competitively tendered in accordance with EC Regulations. The Framework Agreement reduces the need to individually tender each contract and therefore simplifies the design process, generally saving time and allowing an earlier construction start date.

Other legitimate expenses, are included in the accepted cost of the requisitioned works, include; design and supervision fees, site investigation costs, service diversion costs, land access, easement  and discharge consent costs, surveyor and legal costs, compensation and administration.

In the event that the Requisitioner fails to pay the necessary Final Payment Contribution within the offer validity period (28 days), it may be necessary to include a cost adjustment. Connection Charges and Infrastructure Charges are payable in addition to the costs for the requisitioned works.

Call Services First Limited For Further Information on 0207 536 2778—Application-to-requisition-a-public-sewer.pdf

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