When does a property owner need a build over agreement?


Building, or working on or around (within three meters of) any sewer needs the permission of the sewer owner. This could either be the water authority, where the sewer is publicly maintained, or the property owners which the sewer servers, where the sewer is privately maintained.  

This is because sewerage owners, especially water authorities, prefer any works affecting pipes that serve the property to be modified so as not to affect the sewer, or to divert the sewer away from the proposed building work to prevent damage.

There are also a few exceptions as to when an agreement is required, such as the erection of fences as long as it can be easily removed.

Private vs public sewers

Generally, a public sewer is one that is owned and maintained by a water authority. Private drains and sewers however are privately owned, and they are the responsibility of the properties that use them.

As of 1st October 2011, most private sewers and lateral drains which before 1st July 2011 “communicated with” a public sewer was automatically transferred to the water authority.

Therefore, all sewers and lateral drains constructed after 1st July 2011 are private, unless adopted by a water authority, as per the Water Industry Act 1991.

Implications of not having a Build Over Agreement with public sewers

If there is no build over consent available and the water authorities becomes aware of the lack of it, they have the power to remove any structures that block access to the public sewer or those which endanger the structure of the drain. In doing so, the water authorities will not be liable to the property owner for any damage caused.

Additionally, without a build over agreement, the Local Authority’s Building Control department might not sign off on the building regulations completion certificate. This could cause issues, especially if the property owners are considering selling their property in the future.

Where the property owners are selling their property, they need to be aware that prospective buyers obtain a drainage and water search report during the purchase process as standard. The report will detail whether there is a build over agreement and provides purchasers with a plan indicating the position of any water and drainage pipes. Therefore, if there is no build over agreement, purchasers and their solicitors will most likely ask the property owner to rectify this issue, especially if they have a lender involved. This could mean additional costs are incurred by the property owners and delays in the sale process.

Rectification options where there is no Build Over Agreement for public sewers

Indemnity Insurance

Obtaining a build over agreement indemnity insurance will ensure protection for the property owner against any financial loss which arises from building over or near a public drain or sewer without Local Authority and/or water authorities’ consent. This option will usually be the quickest and cheapest option. An indemnity policy will also avoid alerting the Local Authority and/or water authorities to works they might not have agreed to.

Retrospective Consent from the Water Authority

Another option is to approach the water authority and obtain retrospective consent. However, there is no guarantee that consent will be given and even if consent is obtained, the property owner may be requested to make changes to the property to which could result in significant expenses being incurred.

Additionally, property owners may not be able to obtain indemnity insurance once the water authority has been notified of the issue and existing indemnity insurances can be voided by approaching the water authority for consent.

Nonetheless, this option is arguably the better option when considering rectification. This is because an indemnity policy simply acts as a protection against the risk of action being taken by a water authority and it does not remedy the fact that there is no agreement in place, whereas retrospective consent achieves this.

How Pinney Talfourd can help?

For more information please contact our Residential Property department here.

The above is meant to be only advice and is correct as of the time of posting. This article was written by Zeliha Sari, Trainee Solicitor in the Residential Property team at Pinney Talfourd LLP Solicitors. The contents of this article are for the purposes of general awareness only. They do not purport to constitute legal or professional advice. Specific legal advice should be taken on each individual matter. This article is based on the law as of March 2023.



Zeliha Sari

Zeliha Sari

Trainee Solicitor

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