Wastewater connection FAQs

If the new bathroom or kitchen requires a new connection into a public sewer or you are making changes to the existing flow discharging to the public sewer you will need to apply for approval for this connection. If you are connecting to the public sewer, you will always need to apply for the Wastewater Connection Application (Section 106).

If you are connecting to the private sewer and adding additional discharge load or splitting the property into additional units, you will need to apply the Wastewater Connection Application (Section 106).

You will not need to apply, if you're connecting to your private sewer  and there are no additional flows or you're not splitting the property into additional units, you can make this connection yourself using certified contractor, without a sewer connection application. This will need to be monitored/signed off by your local building control officer.

Connections can be made directly to a public sewer or indirectly through a private drain that discharges to our public sewers. If you need to lay your pipe through third party land, such as a neighbour’s property, then you will need their permission before doing so. The below diagram indicates who is typically responsible for which sewers. The ownership of lateral drains is affected by the Transfer of Private Sewers 2011.

As a general rule the only drains that a property owner is responsible for are those within their property and inside the property boundary providing they are not shared with a neighbouring property. Privately owned cesspits and septic tanks and their associated pipework remain the responsibility of the property owner, as do privately owned pumping stations that serve only one property within the property boundary.

You will need to employ a contractor to complete your sewer connection for you. Sewer Connection application only covers the approval that the sewer connection is being completed as per our required standards. The actual work of connecting your property to the sewer main should be done by your qualified contractor.

You will need to search for a qualified contractor to complete your sewer connection works for you. There are usually plenty of options from individual contractors to small firms that can help you.

Once you have appointed your contractor, please ask them to share the following information with you:

• A copy of their health and safety policy
• A copy of their public liability insurance policy (min £5 million value)
• A statement in respect of quality assurance standards for the company's work
• Details of previous sewer connection works, types of connections, depths, methods used and dates.
• Confined space trained personnel to City & Guilds 6150 (minimum 6150-02) where works involve entering a manhole

Also please share the Sewer Connection technical guidance with your contractor, to make sure that your sewer connection is completed according to Southern Water standards.

The foul sewer carries used wastewater to a sewage works for treatment. The surface water sewer carries uncontaminated rainwater directly to a local river or stream.

Only rainwater run-off from roofs or land relating to a building, should be connected to a surface water sewer. All other wastewater from sinks/toilets/baths/showers/washing machines/dishwashers/process water should be connected to a foul sewer.

You can purchase and view our sewer and water maps online. Where known, the map identifies the location of the public sewers and the size and material of the sewer pipe.

If you need to cross third-party land to make the connection to the public sewer you must first get permission from the landowner. Our sewer connection approval of the connection does not grant you permission to cross third party land.

Before any opening is made in the road, footpath, or verge, you’ll need to get a ‘road opening notice’ from the appropriate Highway Authority. They’ll be able to provide you with all associated costs, procedures and timescales required for this.

A private sewer is a drain that has not been adopted by Southern Water or is not our responsibility to maintain. Often this is the section of pipe that is within the boundary of your premise and drains wastewater from your property only.

If the pipe is shared with an adjoining property, it may be a public sewer that Southern Water is responsible for maintaining. In 2011, there was a transfer of private sewers into our ownership with further information available on our website.

If all options have been explored and you have provided evidence that the only option is to discharge surface water into the foul network, then you will need to make an application for a surface water sewer connection.

Section 106 of the Water Industry Act does not permit the discharging of surface water into a foul only sewer unless there are no other surface water provisions available. This is supported by regulatory guidance which states that robust evidence must be provided to the water company supporting the proposal. 

Should you wish to discharge surface water into a foul only sewer, you will need provide the following evidence to support your application:

1.  A capacity check report (by submitting a pre-planning enquiry wastewater application.) of the foul sewer you propose to discharge to
2. A Percolation test confirming your surface water cannot be discharged into the local ground
3. Confirmation from your Local Lead Floor Authority and Local Planning Authority that it is not reasonably practicable to discharge surface water to the ground via infiltration or to a watercourse for the whole or part of the site
4. Written confirmation from you that there are no surface water sewers, drainage systems or watercourses that can receive the discharged surface water

Surface water discharging into a foul only sewer can increase the risk of that sewer becoming overwhelmed in wet weather, causing issues such as flooding and restricted use of facilities for existing customers. As such we will only permit it as the last available option. 

Any surface water flows proposed for discharge into a foul only sewer must be attenuated and controlled at source, this is to ensure that the flow does not cause a reduction to the level of service provided to existing customers.

Under Section 106 of the Water Industry Act 1991 you must inform us if you would like to connect your new or existing property to our public sewerage system. This applies for both foul water and surface water (rainwater) connections. The application needs to be submitted so that we can ensure your connection proposals are in line with our standards and will not be detrimental to the public sewerage system. It is a criminal offence to connect to our public sewer without our formal consent.

The application fee covers our time for processing your application, technical reviews of submitted plans, discussing, and agreeing any changes and undertaking a site inspection of the connection. Please note these charges are per connection, not per application and do not include any construction works.

No, you can submit one application form for multiple connections but there is a separate fee for each sewer connection approval that is required. If you need separate foul and surface water connections, you will need to select option “Combined sewer connection” and specify in the comments how many of each type you need.

If you have applied for the sewer connection and received an approval for us it will be valid for 2 years. You will need to re-apply for the approval to be re-issued when:

• Your sewer connection approval has expired after 2 years
• You change the point of connection from that which was approved
• You change the applicant/contractor carrying out the connection

Your capacity check report is valid for 1 year. You will need to re-apply if the time gap between your capacity check and the actual sewer connection application exceeded 1 year.

In this case, we are approving the new communication to the public sewer not the physical connection. We also require an application so that we have details of the connected properties for billing purposes. Please note that if you do not own the private drain/sewer, you will need to get an approval from the owner first before making your application to us.

Commercial customers in England and Wales have a choice of who they purchase their commercial wastewater services from. Where these companies require sewer connections for commercial purposes, be that temporary building connections, sheltered accommodation, student accommodation or business premises, they need to contact the market retailer of their choice, of which a list can be found on Open Water.

If there is a site with both domestic and commercial elements, then the sewer connection for the domestic elements will need to be applied for through Developer Services and the connections for the commercial element through the market retailer of the developer’s choice.

Once we have installed your commercial supply, the retailer you have nominated in your application, will bill you. If you do not nominate a retailer, we will appoint one on your behalf.

The use of plastic pipes will not be permitted within the public sewer or lateral drain, unless the plastic pipe can withstand 2600 psi jetting pressure and in line with our Southern Water requirements in discussion with us. Certificates of conformity (in date) will need to be supplied, as will technical specification sheets demonstrating conformity with the DCG, and test certificates showing it can withstand a minimum jetting pressure of 2600 psi in accordance with WIS 4- 35-01 with your application.

To confirm that the sewer you propose to connect your flow to is connected to the public network.

Our policy, Building Regulations 2010 Approved Document H and the Water Industry Act 1991 requires that where separate foul and surface water sewers are provided, the foul and surface water should drain to their respective sewers.

If there is no surface water sewer nearby, you should consider disposal of surface water to the ground using soakaways, or to a local watercourse.

If all options have been explored and you have provided evidence that the only option is to discharge surface water into the foul network, then a capacity check will be required to assess if this can be accommodated. You will need provide the following evidence to support your application:

1.  A capacity check report (by submitting a pre-planning enquiry wastewater application. ) of the foul sewer you propose to discharge to
2. A Percolation test confirming your surface water cannot be discharged into the local ground
3. Confirmation from your Local Lead Floor Authority and Local Planning Authority that it is not reasonably practicable to discharge surface water to the ground via infiltration or to a watercourse for the whole or part of the site
4. Written confirmation from you that there are no surface water sewers, drainage systems or watercourses that can receive the discharged surface water

Under section 111 of the Water Industry Act 1991, you must not discharge:

• any matter likely to injure the sewer or drain, to interfere with the free flow of its contents or to affect prejudicially the treatment and disposal of its contents; or
• any such chemical refuse or waste steam, or any such liquid of a temperature higher than 43 degrees Celsius, or
• any petroleum spirit or carbide of calcium. This means that fats, oils and grease (FOG), commonly discharged from restaurants are not permitted.

No, both land drainage and highway drainage should not be discharged to the public sewer. For land drainage this should be dealt with on site or using alternative means such as soakaways or discharge to a watercourse. For highway drainage, any proposed surface water connections to the highway drains will need the approval from the respective highway authority.

A direct connection is any connection that is made to any public sewer. An indirect connection is a connection to a private sewer or drain that then goes into a public sewer. A private drain is an existing pipe that only serves 1 property and is within the property boundary.

There are risks associated to working on a public sewer and as part of the application process we must check your contractor is aware of those risks and the work will be carried out safely whilst minimising the risk to those on site, to the public and to the integrity of the sewer network.

Your contractor should have a Health and Safety policy and you are also required to submit a site- specific risk assessment and method statement, if 5. If you are connecting to the sewers 5 metres deep or 300mm and above.

Download Risk Assessment and method statement template

An Infrastructure Charge is also applicable for all properties connecting to the public sewer (or a sewer or drain which discharges to the public sewer) for the first time. It is charged in addition to the application fees and is due after the connection has been made. You can find out more by reading our connection charging arrangements.

Non-domestic premises will be individually assessed according to the number of appliances/fittings producing wastewater. (VAT is zero rated for new domestic property connection to the sewerage system). Infrastructure charges are applicable even if the connection is made via a private sewer providing that the private sewer ultimately discharges into the public system.

These costs do not cover the cost of laying the drain from your property to the sewer or making the connection, which is something you will need to arrange with a competent contractor.