We scored Australia's biggest plumbing companies on AI visibility. Here's what we found.

It started with one plumbing business's question: why don't we show up when a customer asks ChatGPT to recommend a plumber? To answer it properly, we didn't just look at their site - we ran the same check across Australia's 100 largest plumbing companies. The results were not what you'd expect. The average business scored 68.8 out of 100 for AI visibility, nearly nine in ten had no supporting statistics anywhere on their pages, and - the finding that surprised us most - being bigger didn't help.

How we measured it

Every company's public website was scored against the AISearch Global AEO Score Calculator - 20 signals in total. Seventeen are answer-engine-optimisation checks (structure, schema, clarity, entity signals), and three come straight from the peer-reviewed Princeton GEO study: on-page statistics, quotations, and cited sources, the three content changes shown to lift AI citations by 28–41%.

No private, paid, or scraped data was involved. Every signal we scored is sitting in plain sight on each company's own website - which is exactly what an AI model sees when it decides who to recommend.

What we found

The gaps clustered in three places - and they're the same three whether the business turns over five million a year or fifty.

Size didn't predict visibility

This was the headline. Some of the largest, most-advertised names on the list scored below far smaller competitors. AI visibility isn't bought with brand recognition or ad spend - it's earned by how a page is written and structured. A two-van operator with a clearly written services page can out-rank a national franchise in an AI answer, because the model can actually understand and trust what the page says.

The fixes are cheap - that's the frustrating part

None of the top gaps need a redesign or a developer. Adding a genuine customer quote, replacing "trusted by hundreds" with "187 jobs completed across Western Sydney since 2019", and cutting the keyword stuffing are often a single afternoon's work. The businesses aren't losing AI visibility because it's hard - they're losing it because nobody told them the rules changed.

The free tool that came out of it

While we were deep in the plumbing world, one thing kept coming up in the businesses we looked at: hard water. Plumbers spend half their quotes explaining why scale wrecks pipes and hot-water systems - and customers rarely believe it until they see it. So we built a small thing to help.

The Hard-Water Scale Impact Visualizer is a free, no-login tool: a customer enters an Australian postcode and watches a pipe's bore shrink as scale builds over the years. It's the maths behind the quote, in plain sight - a by-product of the research, and genuinely free for any tradesperson to use or hand to a customer.