Public Sewers and Building Works: Guidance on Compliance and Consent
On 1st October 2011, ownership of private sewers and lateral drains was transferred to the water and sewage companies (Wessex Water, Thames Water, Severn Trent etc., dependent on location). These are now public sewers. If you are planning on building on your property, you must be aware of public sewers and build accordingly.
Identifying a Public Sewer
If the sewer is within the boundaries of the property and serves only the property, it remains private, and the following does not apply.
If it was previously a private sewer or lateral drain (i.e., if it serves more than one property), it is owned by the water company and is a public sewer.
Do not rely on the sewer search map to locate all public sewers – the company may not yet have mapped sewers. Look for manhole covers when you visit the property.
Building Near or Over Public Sewers
Your local water company is responsible for maintenance of public sewers. It has a statutory right to access public sewers, even if they are beneath your land. Therefore, they may remove, alter, or damage buildings to gain access.
Before building on or near to a sewer, it is worth considering whether you can divert the sewer or avoid it by modifying your plans.
If you build over a public sewer without an agreement and the water company needs access, they will remove structures which block access. They are not liable for damage caused in the process.
Build Over Agreements
Building on, over or close to (i.e., within 3 metres of) a public sewer is not permitted without consent. This consent is known as a ‘build over agreement’.
You must apply to the water company for a build over agreement. You can normally do this on their website, by email or by post.
If you are purchasing a property, part of which appears to be within 3 metres of a sewer, we will need to ensure that an agreement was provided (if built after 2011), or the appropriate building regulations and planning permissions were obtained (if built before 2011).
If No Agreement Was Entered Into
In the absence of an agreement, you may obtain:
- Indemnity insurance: to protect against loss incurred because of the sewer being built over without an agreement.
- Retrospective consent from the company: this might be available, but there is no guarantee of consent if applied for. Once you have applied for retrospective consent and notified the company, indemnity insurance is unavailable.
Expert Conveyancing Advice on Build Over Agreements
At Nantes Solicitors, our conveyancing team ensures your property transactions and building projects comply with all legal requirements, including build over agreements for public sewers. With offices in Bridport, Dorchester, Weymouth, and Portland, we provide clear, practical guidance to protect your interests and avoid costly issues. To speak with a solicitor, call us on 01305 771000 or visit our contact page.
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