Sustainable Drainage Systems (SuDS)

The SAB is a statutory function delivered by the local authority to ensure that drainage proposals for all new developments where the construction area is 100m² or more and that have drainage implications are designed and built in accordance with the national standards for sustainable drainage published by Welsh Ministers. A SuDS application demonstrating compliance with the statutory SuDS standards for the design, construction, operation and maintenance of surface water drainage systems serving new developments must be submitted to the SAB for approval.

In our capacity as a SAB we will:

• Evaluate and approve drainage applications for new developments where construction work has drainage implications.
• Adopt and maintain surface water drainage systems according to Section 17 of Schedule 3 (FWMA). It is important to note that the SAB will only undertake its duty to adopt systems that have complied to the statutory standards. Developers will need to enter into a legal adoption agreement as a part of the consent process.
• Approve but will not adopt a drainage system in a publicly maintained road. Publicly maintained roads are those to which section 41 of the Highways Act 1980 applies.

Contact Us: 

Via e-mail: SABregistrations@carmarthenshire.gov.uk
Via telephone: 01267 228828

There is a large amount of information available, and the following webpages are a useful free resource to gain more information on Sustainable Drainage and help you understand what you will need to consider.

Welsh Gov’t FAQs

SuDS Wales

Susdrain

This legislation came into force from January 7^th 2019. Existing sites and developments with planning permission granted or deemed to be granted (whether or not subject to any conditions as to a reserved matter) or for which a valid application has been received, but not determined by 7^th January 2019, will not be required to submit a SuDS application.

Approval will still be required if the planning permission was granted subject to a condition as to a reserved matter and an application for approval of the reserved matter is not made before 7^th January 2020.

All construction work which has drainage implications where the development or redevelopment is more than a single dwelling house or involves the construction of a building or other structure covering an area of land equal to or greater than 100m² (unless it falls under one of the specific exemptions or transitional arrangements) requires SAB approval.

In the legislation for sustainable drainage:

• Construction work means anything done by way of, in connection with, or in preparation for the creation of a building or other structure, and
• Construction work has drainage implications if the building or structure will affect the ability of the land to absorb rainwater.
• Construction area is generally defined in the regulations for sustainable drainage as the construction of a building or other structure covering an area of land of 100 square metres or more.

Guidance on completing the full application form

We are not responsible for approving and, consequently do not adopt, a drainage system which:

• Forms part of the strategic road network
• Forms part of the national rail network
• Forms part of a harbour
• Serves permitted development under 100m² 
• Is constructed by the internal drainage board under its functions in the Land Drainage Act 1991

If you have drainage design and wish to have feedback on this prior to a full application submission, please take the opportunity to formally submit a SuDS Pre Application Opens in a new tab.

We offer a pre-application service to discuss in detail your site’s drainage requirements and what needs to be submitted with your application.

This will ensure suitability of proposed SuDS design in line with national standards and adequate site layout. We strongly recommend that you use this service before you submit your full application, to limit delays to approval and reduce cost in the long term.

If you have obtained positive feedback from the SAB regarding your SuDS Pre Application you will need to submit a SuDS Full Application for assessment and approval for your project to progress to potential construction stage.

Submit a SUDS Pre-Application Opens in a new tab

If your number of dwellings is known, please use Calculator 1.

If the number of dwellings is not known and the gross floorspace of buildings and/or land created or changed (i.e. anything other than residential dwellings) (m2) is known, please use Calculator 2.

If neither the number of dwellings or gross floorspace of buildings and/or land created or changed known, please use Calculator 3.

Please note that the area of construction used to calculate the fee should ALSO include for such items as; driveways, pathways, landscaping, garages, workshops, patios etc regardless of whether they could be considered permeable in their constructed form. 

Convert acres to hectares
Convert Square Meters to hectares

Please Refer to Welsh Government Advice Note WG42458 - SAB Applications for Agriculture Buildings, Covering & Clean Yards.

The minimum requirement for a SAB Application to be valid is:

• Full Payment of the correct SAB application fee: link to calculator
• A site location plan, indicating site boundaries (with North identified)
• A plan specifying the construction area and drainage strategy
• A formal maintenance plan outlining maintenance activities, how often these will be undertaken and who is responsible for those activities
• Surface water calculations for proposed SuDS elements
• A statement on whether or not the application relates to a development that is the subject of an Environmental Impact Assessment (EIA) application

In addition:

If Rainwater Harvesting is not proposed, then percolation test results will also be required (we require the test to be completed and submitted to BRE365 standards).

If The only viable option for the application involves a proposed connection to an existing sewer network then Permission/ Agreement in Principle will also be required from the sewer owner.

Highway Drainage: HighwayDrainConnect@carmarthenshire.gov.uk

Welsh Water: developer.service@dwrcymru.com
Please note that a submission missing any of the requirements will not be valid.

Once all the information is received, to the satisfaction of the SAB, the SAB will have 7 weeks to determine an application; however, if the application is subject to an Environmental Impact Assessment it will have 12 weeks for SAB determination.
Therefore, we strongly recommend you use our pre-application service Opens in a new tab before submitting a full application.

Please send your SuDS Application to SABRegistrations@carmarthenshire.gov.uk

Download SuDS application form Opens in a new tab

To increase the likelihood that a SuDS Full Application is successfully validated, we recommend that you submit a SuDS Pre-Application. The SuDS Pre-Application Opens in a new tab simply outlines in principle how you intend managing the surface water from your development. The SAB team can then provide you with feedback regarding your drainage proposals prior to you submitting and paying for a SuDS Full Application.

Fees are calculated based on the size of the construction area.

• You do not need to apply for construction areas less than 100m² (unless the application is for more than one dwelling)
• You need to submit the appropriate fee with your application
• There is a 50% reduction for applications submitted by community councils

Convert acres to hectares
Convert Square Meters to hectares

Please note that the area of construction used to calculate the fee should ALSO include for such items as; driveways, pathways, landscaping, garages, workshops, patios etc regardless of whether they could be considered permeable in their constructed form.

Inspection Fees: 

If your application is approved, there will normally be a minimum of one site inspection and associated fee of £168. You will receive an invoice for this along with your SAB consent.

If you have a large site, or a site where the drainage is being adopted by the SAB, then multiple inspections will be conditioned. This will be done, in consultation with you, the applicant or agent, and will be charged at £168 per inspection. These inspections will ensure compliance with the approved consent.

These fees are based upon The Flood and Water Management Act 2010, Schedule 3, The Sustainable Drainage (Application for Approval Fees)(Wales) Regulations 2018.

You will need to provide the following details when making your payment - type of application, application reference number or name and application location if you do not have a reference number yet and the correct application fee.

• Online - Pay online at the same time as you submit your application form, this is the most efficient way to pay and will avoid any delays in processing your application. 
• By Telephone - We accept Maestro, Solo or Visa debit cards. If you’d like to speak to a member of staff in the cashier's team - call 01267 228686 during office hours, 9am - 5pm.
• By post - Make cheques payable to ‘Carmarthenshire County Council’ and post to: SAB Registrations, Civic Offices, Crescent Road, Llandeilo, SA19 6HW.
• In Person - You can make a cash, credit/debit card or cheque payment at your nearest Hwb in Ammanford, Carmarthen or Llanelli.
• BACS Payment - email SABRegistrations@carmarthenshire.gov.uk for further details and to set up a BACS payment.

Please note, should you choose to pay by telephone, post, in person or BACS, you application will not be processed until the payment has been reconciled which will create a slight delay.

What is the normal timeframe for decision?

• A decision is taken on the valid application by the SAB Team within 7 weeks
• If the development is subject to an Environmental Impact Assessment (EIA) it can take 12 weeks
• If the decision cannot be made within the 7 or 12 week time scale due to additional information being required or due to the requirements of consultees then we will ask you to agree to an extension of time
• Please note that valid applications can be approved or refused
• Approved valid applications will often have conditions attached that must be complied with before construction work can commence on site
• Please note that construction work includes site preparation works for the whole development

An approved application is valid for 5 years. 

Environment Impact Assessment (EIA) Statement:

Environmental Impact Assessment (EIA) is a tool used to assess the significant effects of a project or development proposal on the environment. EIAs make sure that project decision makers think about the likely effects on the environment at the earliest possible time and aim to avoid, reduce or offset those effects. For more information, please visit the UK Government website.

Flood Risk Assessment:

A flood risk assessment (FRA) is a document that reviews a development in its proposal form to assess it against the risk of flooding, whether that be from groundwater, river (fluvial), surface water (pluvial), estuary/coastal (tidal), or from sewer sources. For more information, please visit the UK Government website.

Surface Water Discharge Hierarchy:

Surface water drainage arrangements shall demonstrate the proposed surface water drainage complies with National SuDS Standards. As much of the runoff as possible should be discharged to each hierarchy element before a lower hierarchy element is considered (the lowest hierarchy element being 5). Collection and infiltration methods of drainage are required to be considered in the first instance.

Please note the following:

• Hierarchy 2 - If infiltration is proposed, the developer must provide evidence that infiltration is viable at the site by acceptable testing methods and design the infiltration system according to the results obtained. Failure to provide the necessary evidence at submission stage will prevent your application progressing to the technical assessment stage of your SuDS Application.
• Hierarchy 3 - If it is proposed to discharge partially or fully to an existing watercourse, the developer must provide; evidence that infiltration is not viable, necessary Flood Consent permissions if required and permission from third party riparian owners if a connection is outside the boundary of the development site. Failure to provide the necessary evidence at submission stage will prevent your application progressing to the technical assessment stage of your SuDS Full Application.
• Hierachy 4 - If it is proposed to discharge partially or fully to an existing surface water sewer, the developer must provide; evidence that infiltration is not viable, evidence that discharge to an existing watercourse is not feasible or permitted and evidence that necessary permission in principle is available from the asset owner of the existing surface water sewer. Failure to provide the necessary evidence at submission stage will prevent your application progressing to the technical assessment stage of your SuDS Application. Additionally, if it is proposed to connect directly to an existing Carmarthenshire County Council Highway surface water sewer infrastructure asset, the applicant should contact Highways Drainage: HighwaysDrainConnect@carmarthenshire.gov.uk to gain agreement in principle to connect prior to submitted their SuDS Full Application.
• Hierachy 5 - If it is proposed to discharge partially or fully to an existing combined sewer, the developer must provide; evidence that infiltration is not viable, evidence that discharge to an existing watercourse is not feasible or permitted and evidence that discharge to an existing surface water sewer is not feasible or permitted. Failure to provide the necessary evidence at submission stage will prevent your application progressing to the technical assessment stage of your SuDS Full Application.

Infiltration Assessment:

The infiltration rate is the velocity or speed at which water enters into the soil. It is usually measured by the depth (in mm) of the water layer that can enter the soil in one hour. For more information, please visit the UK Government webstie.

The following additional fees and information will be applicable where larger developments required SuDS Adoption, for example, a SuDS Adoption Agreement Document. 

Please refer to section 11 of the SuDS Full Application Form for guidance and the following guide - SAB Adoption Workflow

Inspection Fees: 

If your application is approved, there will normally be a minimum of one site inspection and associated fee of £168. You will receive an invoice for this along with your SAB consent.

If you have a large site, or a site where the drainage is being adopted by the SAB, then multiple inspections will be conditioned. This will be done, in consultation with you, the applicant or agent, and will be charged at £168 per inspection. These inspections will ensure compliance with the approved consent.

These fees are based upon The Flood and Water Management Act 2010, Schedule 3, The Sustainable Drainage (Application for Approval Fees)(Wales) Regulations 2018.

Temporary Bond: 

Approved applications could also incur additional fees or insurance provision for temporary bonds that may be required to secure the construction work for the drainage system. These costs vary dependent on the nature and scale of the work. You will be made aware of the requirements as part of the approval process and are predominantly associated with large developments.

Temporary bond fees or amounts are based upon the estimated capital cost of completing all the SuDS Infrastructure elements of the development.

Commuted Sums:

If you have a large site, or a site where the drainage is being adopted by the SAB, then a commuted sum will be conditioned as part of the SAB consent and will form part of a formal SuDS Adoption Agreement for the development. The sum ensures that future funding for maintenance or replacement of SuDS infrastructure items being adapted by the SAB are in place.

Securing a sustainable funding mechanism for the lifetime of development is a key objective of the SuDS Approving Body (SAB). The SAB has a responsibility for the management and maintenance of SuDS assets after they have been adopted. Therefore, commuted sums aims to ensure that the SAB has the resources to cover the upkeep and (where appropriate) the replacement of the assets they have adopted. The effectiveness of SuDS and the associated multiple benefits will rely on appropriate maintenance.

In order to ensure consistency throughout Wales, the use of the industry standard guidance “Commuted Sums for Maintaining Infrastructure Assets” prepared by the CSS (County Surveyors Society), is to be used, to calculate commuted sums for all drainage assets being adopted by the SAB, whether that be through a S38 agreement or a bespoke legal agreement for the life of the developments (60-120 years).

The calculation of a commuted sum includes consideration of:

• The estimated periodic maintenance cost of the asset to the adopted e.g. every six months. The SuDs manual provides useful information on this element.
• Its future cost of renewal or replacement (e.g. permeable paving has design life of 20 years, over the lifetime of the development this could lead to 3 replacements).
• The duration over which the sum is required. The Association of Directors of Planning and Transport recommends commuted sums for structures should be calculated to cover a 120-year period and that the period for other items should be 60 years (basically the whole life of the development).
• The effective annual interest rate that will provide a return on the sum invested prior to its expenditure after the effects of inflation have been taken into account (called the discount rate approx. 2.2%).

The use of the CSS guidance is recommended to provide a common understanding for developers and the SAB.