Actionable nuisance in Scotland – how bad does a smell need to be?

William MacBean v Scottish Water [07.07.21]

Cases examining the law of nuisance are rare in Scotland. It is even more rare that they go to appeal. The case of William MacBean v Scottish Water did just that in July 2021 and it is a useful consideration and reminder of the fundamental principles of a claim in nuisance under Scots Law.


The case concerns Scottish Water’s sewage works, or waste water treatment plant (WWTP) to give it its proper title, in the picturesque village of Boat of Garten in the Scottish Highlands. The WWTP is situated 17 metres from Mr MacBean’s home, having replaced another WWTP in 2015, which had been around 50 metres from his home.  

When the planning application was submitted, Scottish Water made a number of errors. The most notable were to state the distance as 70 metres rather than 17, and that the new WWTP would not create any odours. Scottish Water accepted that these statements were incorrect, and even one of their own experts in the case commented that all WWTPs create some odour.

It was those odours that led to this court action, described by Mr MacBean as “strong, intense and offensive”. In January 2019, Scottish Water effectively conceded that the odours were causing a nuisance, and on joint motion, a declarator of nuisance was pronounced. Importantly, the judge did not grant an interdict (injunction) at that stage. Instead, things seemed quite amicable and Scottish Water were given the opportunity to remedy matters while still operating the WWTP.

When the case called again for a further proof in March 2020, Mr MacBean argued that the odours were continuing at a level which constituted a nuisance. It was accepted that there had been some amelioration but that the odours were present to such an extent that he was unable to hang out washing or sit in his garden. He led evidence from neighbours and friends, alongside expert evidence on the operation of WWTPs.  

Remedial works had been carried out, and Scottish Water argued that any remaining odours were faint, transient and localised in nature. Crucially, they appointed two independent companies to monitor and conduct smell assessments, to include responding to any complaints by Mr MacBean or others. Their results tended to show that the odours were indeed faint, transient and localised. Their independence and the method in which the companies carried out their work and gave their evidence led the first instance judge, Lord Woolman, to prefer their evidence.

Accordingly, Lord Woolman found that there was no ongoing nuisance. In a judgment issued on 7 July 2021, the Inner House of the Court of Session (Scotland’s Court of Appeal) upheld that decision. They accepted his approach to the established law of nuisance, and that is worth considering here.

Nuisance – the test

The authoritative test in Watt v Jamieson [1954], was refined into two questions:

1  Was there an exposure?
A question of fact, and in this case summarised as: “Do odours from the WWTP still come on to Mr MacBean’s land?” This was the easy part, as it was accepted that some odour was indeed continuing.

1 Would a reasonable person tolerate the exposure?
That is an objective test and, throughout, due weight must be given to all the surrounding circumstances of the offensive conduct and its effects. As noted, the efforts taken by Scottish Water and the results of the independent testing carried out on their behalf, found favour with the judge and as such, he held that odours were at a tolerable level to the reasonable person.

In addition, the following points were considered to be important surrounding circumstances:

  • Scottish Water did not intend to cause the nuisance and took careful steps to try to cure the problem.
  • There were few complaints made, other than by Mr MacBean.
  • The WWTP performs an important public service.


The case does not make new law, but it provides a useful illustration of the application of long-held authority on the Scots law of nuisance. The question of whether there is exposure will always be a factual one, but the impact of that exposure must be at a level that would be intolerable to a reasonable person. Strong objective evidence is required to satisfy that test, and if means allow, a period of independent testing in the manner adopted by Scottish Water will undoubtedly be the best evidence.

As an aside, it was interesting to see that the court restricted Scottish Water’s expenses (costs) to 75% as, although they were successful, some recognition had to be given to the fact that parties were only in this position as a result of their initial nuisance. We are seeing more cases where the court moves away from the rigid rule that expenses simply follow success, and that is to be welcomed.

The Inner House also praised the brevity of Lord Woolman’s decision in getting to the heart of the issue both generally and in the specific circumstances of the case. Concise judicial opinions are also to be welcomed!