What is a Section 106 sewer connection?

Section 106 of the Water Industry Act 1991 gives property owners the right to connect to the public sewer, subject to conditions. The water company must be given 21 days notice and will specify the connection point, method and any conditions. A fee is charged for the application and supervision.

What is a build-over agreement?

If you are building within 3 metres of a public sewer, or directly over it, you need a build-over agreement from the water company. This ensures your building works do not damage the sewer or prevent future access. A CCTV survey before and after construction is usually required.

Do I need to pay a bond?

Some water companies require a bond (financial guarantee) for larger connections or development work. This is refundable once the works are completed satisfactorily and the final inspection is passed. The bond amount varies but is typically £1,000-£5,000.

How much does a sewer connection cost?

The water company fee for a standard S106 connection is typically £200-£500. Add to this the contractor cost for the physical connection work (typically £1,500-£3,500 depending on depth and road/footpath reinstatement). Build-over agreements add £150-£400.

Can I connect surface water to the foul sewer?

Only if your area has a combined sewer system. In areas with separate sewers, surface water must connect to the surface water sewer or be disposed of via SuDS (soakaways, permeable paving). Your water company sewer map will show which system serves your property.

TradeCalculator.co.uk

Drainage Connection Fee Calculator — S106, Build-Over & Bond Costs

Estimate water company Section 106 sewer connection fees, build-over agreement costs, bond requirements and inspection charges.

Water Company

Connection Type

S106 Connection Fee

Per connection (check water company website)

Number of Connections

Number of separate connections

Build-Over Agreement Needed

Building within 3m of public sewer

Build-Over Fee

Check your water company's charges

Bond Amount

Refundable bond if required

Inspection Fee

Per inspection visit

How We Calculate This

This calculator estimates the total fees payable to the water company for a new sewer connection, including all application and inspection charges.

The formula

Total Fees = (S106 Fee × Connections) + Build-Over + Bond + (Inspection × Connections) + VAT

Typical fee ranges (2025/26)

S106 application: £200-£500 per connection
Build-over agreement: £150-£400
Bond: £1,000-£5,000 (refundable)
Inspection: £100-£300 per visit

Frequently Asked Questions

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Last updated: March 2026

All calculations are estimates. Verify with your supplier.