Legionella and water hygiene: who AI search cites, and why
Last reviewed 14 October 2026
Part of Building compliance and safety. Measured 28 September 2026. Figures from Ahrefs, UK data. AI citations are counted across the AI platforms Ahrefs tracks. Updated when re-measured.
When someone asks an AI assistant "how often do I need a legionella risk assessment?", the answer is drawn from web pages. We measured 376 UK water-hygiene firms to see whose pages those are. More than half are never cited: 202 of the 376 had no AI citations at all, 42 had twenty or more, and the median firm had none.
Here are two that are cited.
| Measure | Firm A | Firm B |
|---|---|---|
| Visits from Google (UK, per month) | 4,114 | 432 |
| Times cited by AI assistants | 252 | 48 |
| Pages that earned those citations | 74 | 36 |
| Citations per 100 visits | 6.1 | 11.1 |
Two routes to similar results. Firm A has many cited pages and collects citations by volume. Firm B has far less traffic but is quoted more often for each visitor. The two firms are anonymised. Neither figure says anything about the quality of either firm's water-hygiene work.
What the two cases suggest
Our reading: citation volume follows the number of pages that each answer one question. The rate per visit shows that even a small site is quoted when its pages answer the question.
Why it matters for a water-hygiene firm
Our reading: the duty runs continuously, so demand does not spike around a date. UK searches each month: 3,500 for "legionella risk assessment" and 1,800 for "legionella testing" (Ahrefs, September 2026). The firms cited when those questions go to an AI assistant are the ones that wrote the answers. Most of the market has not.
What buyers search for
Eight of the most-searched questions UK buyers type about legionella risk assessment and testing:
| Question, as typed into Google | UK searches a month |
|---|---|
| is a legionella risk assessment mandatory for landlords | 200 |
| do i need a legionella risk assessment | 150 |
| how much is a legionella risk assessment | 150 |
| how often legionella risk assessment | 150 |
| how often should a legionella risk assessment be reviewed | 150 |
| is a legionella risk assessment mandatory | 150 |
| who can carry out a legionella risk assessment | 150 |
| is legionella testing a legal requirement | 100 |
Source: Ahrefs keyword data for the UK, retrieved 13 October 2026. Monthly search volume shows how often a question is typed into Google; it does not show which firm an AI engine cites.
What we would check for your firm
Your citation count across the same engines, the pages earning it, and the questions in your market where a competitor is cited and you are not. That is the SEO & AI Search Sprint: one measured report delivered 3 working days from purchase, once we have agreed your competitor list, for £950. See what it includes.
Questions answered
Is the citation count a ranking of service quality?
No. It counts how often AI assistants quote each site when answering water-hygiene questions. It says nothing about the quality of anyone's water-hygiene work.
Why measure citations per 100 visits?
A site with ten times the traffic collects more citations by volume. The per-visit figure shows whether the content is the kind engines quote, whatever the size of the site.
How was this measured?
Ahrefs, UK data, 28 September 2026: organic traffic and AI citation counts for 376 UK water-hygiene firms.
Can SuccessClick run this for my company?
Yes. The SEO & AI Search Sprint measures your firm against named competitors, delivered 3 working days from purchase, once we have agreed your competitor list, for £950.
Would AI name your firm today? The SEO & AI Search Sprint measures where AI names you and your competitors. The free check takes two minutes.