Connecting to a sewer

Last reviewed:

If you're planning to connect to one of our sewers, you’ll need our consent before you go ahead. That’s because we need to check the connection will work as planned, and that it won’t potentially cause problems like sewer flooding or pollution. We have legal duties around this, set out in Section 94 of the Water Industry Act 1991.

If you’re planning a new development, early discussions with us can help avoid potential delays later in the process. By making a pre-planning enquiry, you’ll find out if our existing wastewater network can support your proposed development. If it can’t, we’ll explain the next steps and timeframes involved in creating network capacity to serve the new development.

We’ve included important information below to help you plan your connection(s). You can also click on this link Guidance for a new connection to a public sewer to learn more about how to get your building work approved. If you don't want to use our online form below, you can download our Sewer connection application form.

Planning to connect

Before we can agree your connection, you’ll need to know where you’re making your connection, the type of sewer you’re connecting to and who owns it.

There are three different types of sewer:

  • Foul water sewers carry waste from appliances such as toilets, baths, showers and dishwashers.
  • Surface water sewers carry rainwater from rooftops, driveways, patios and roads.
  • Combined sewers carry both foul water and surface water.

We don’t permit foul water to be connected into a surface water sewer, because these discharge into rivers and streams.

And we rarely allow surface water to be connected to a foul water sewer, as heavy rainfall can then cause sewer flooding. We only permit this if you can’t discharge your surface water by another method. You’ll need to provide confirmation from your local authority that you can’t use a soakaway, and from the Environment Agency to say you can’t connect to a watercourse.

 

Once you’ve confirmed the type of sewer you’re connecting to, you’ll need to locate the point at which you intend to connect.

There are several ways to do this:

  • Purchase a map showing where local sewers are located.
  • Locate a nearby manhole, which will indicate there is a sewer beneath. If you don’t want to connect at this location, lift the manhole to see which way the sewer runs. Please take care – covers are heavy and you may need assistance and/or specialist equipment.
  • Speak to a drainage specialist.

To check what type of waste the sewer carries, you can open the manhole cover and flush the toilet of a nearby property. If water flows through the manhole, it’s probably a foul water sewer. You can check if it’s a surface water sewer by pouring water down a nearby gully or drainpipe, then seeing if water flows past the manhole.

Before you apply you’ll need to confirm who owns the pipe you propose to connect to.

We own pipework that carries waste or rain water from more than one property. These pipes are called public sewers, and if you want to connect to one, we’ll need to carry out an inspection after you’ve made the connection.

Homeowners own pipework that only carries waste or rain water from their property and is located within their land. These are called private drains.

The ownership and location of the sewer you intend to connect to will determine the type of application to submit:

Connection type Price per connection

Public sewer via lateral drain

Connecting directly to a public sewer on public land

£485

Public sewer on private land

Connecting directly to a public sewer on private land

£278

Highway gully connection

Connecting directly to a highway gully

£277

Adoption site to a public sewer

Connecting an adopted sewer on public land

£273

Indirect connection to a public sewer

Connecting to a private sewer on private land

£87

Once you know the point where you want to connect, you’ll need to create drawings showing full details of your proposals. You can prepare these yourself, so long as you’ve included all the information below, or ask your drainage consultant to do this.

In order to review the application and issue consent, we’ll require a site location plan indicating:

  • The type of connection (surface water, foul water or combined)
  • The location of the connection (separate points should be labelled individually)
  • The size of the proposed connection
  • The size of the sewer
  • The level of connection (interpolated)
  • The method of connection (e.g. manhole or junction)
  • Details of planning conditions (if applicable)
We’re responsible for reviewing your application and providing consent for you to connect to our sewer network. You should find a qualified contractor to make the connection, as we’re currently unable to offer competitive quotes for this service, unless you’re connecting to a trunk or strategic sewer. However, we will need to inspect the connection.

Terms and conditions

Once you have drawings showing your proposed connection in detail, you can:

Apply to connect to a sewer

For information on the steps after you apply, look at our section on getting you connected.

Trunk sewers

Trunk sewers collect the flow of sewage from local areas/sewers, rather than individual homes or developments. Connecting directly to them can be complex and dangerous, which means we often refuse permission. In this case, you’d need to find an alternative sewer or method of discharge.

If we permit your connection, we’ll insist on doing this ourselves under Section 107 of the Water Industry Act.

Implications of connecting to a trunk sewer

When connecting to a trunk sewer you may face delays and additional costs. Among the most common reasons for this:

  • Man entry surveys may be required to determine the line, level and condition of the sewer. These may have to be done at night, when flow in the sewer is less. Heavy rainfall or emergency work could delay this.
  • We’ll often need to talk to the highway authority, to agree any measures needed before we work in a road. Traffic permits, lane closures and other issues can often take months to get authorised, as well as adding to the cost of your work.
  • The method of making the connection can add time and cost. There may also be site restrictions that affect us making the connection at the require time.

     

Process of connecting to a trunk sewer

You can submit your application online.

Apply now

In addition to contact information, you’ll need to provide a site location plan indicating:

  • The type of connection (surface water, foul water or combined)
  • The location of the connection (separate points should be labelled individually)
  • The size of the proposed connection
  • The size of the sewer
  • The level of connection (interpolated)
  • The method of connection (e.g. manhole or junction)
  • The type of sewer you’re laying (e.g. clayware)
  • Details of planning conditions (if applicable)

You’ll also need to provide credit or debit card details, in order to pay the required deposit and charges.

We’ll call you within 14 days discuss the costs, survey, site meeting and construction. We won’t allow connections to trunk sewers in greater London – you’ll instead need to choose an alternative point of connection to a non-trunk sewer, or requisition a new connection and associated pipe laying from us.

Please note that we’ll select a suitable connection point if you apply for a requisition, which might not be the point at which you wish to connect.

We may request additional plans if your application information isn’t sufficient.

Once we’ve scoped the works , we’ll call to tell you the application fee, which you can find in our guide ‘Charging arrangements for new connection services’. You’ll then receive the formal application charges by email or letter. Once we’ve understood the requirements for your connection, we’ll issue a formal quote for the wastewater connection works only.

If you’ve any queries about your quote, please call us on 0800 009 3921. Otherwise you can pay the full amount on your quote, preferably online with your credit or debit card, at thameswater.co.uk/payds. You’ll need to quote the reference number starting ‘DS’ from your quote.

 Pay 

After payment has been received we’ll carry out the survey and send you the report. We'll then issue the consent to carry out the connection.
We’ll call you to discuss the costs of carrying out the connection. You’ll then receive the connection quote and schedule or works via letter.

You can either pay the full amount on the quote in advance, preferably online with your credit or debit card, or pay in arrears if you provide security equal to the expected charges (including an inflation allowance). You’ll need to quote the reference number starting ‘DS’ from your quote. If you’ve any queries about your quote, please call us on 0800 009 3921.

Once you’ve made payment or provided security, we’ll apply for the appropriate traffic management permits and carry out the connection. Once we’ve made the connection we’ll issue you with a completion certificate.