Why one AI recommends your plumbing company and another doesn't

Ask ChatGPT for a plumber in your town and it might name your company. Ask Google's AI the same question an hour later and you are nowhere. Same business, same town, two different answers. Owners see that and assume something is broken. Usually nothing is. The assistants do not share one list, and a company one of them trusts is not automatically a company the others have even noticed.

Here is why that happens, and the part that actually matters for a small shop: what to do about it.

The assistants are not reading the same web

Each AI assistant builds its answer from a different slice of the internet. ChatGPT leans on Microsoft's Bing index and on reference sources it treats as settled fact. Google's AI, both Gemini and the AI answers at the top of a Google search, leans on Google's own index, the same machinery behind ordinary Google rankings. The two pull from different places, so they do not land on the same shortlist.

Researchers have started measuring how little those sources overlap. One 2026 analysis of tens of thousands of AI citations found that about three out of four cited pages showed up on only one assistant, not the others. That study looked at all kinds of questions, not only local plumbing, so do not read it as a law of nature. But the headline holds: the assistants mostly draw from different places, so being known to one is not the same as being known to all.

Why each one leans a different way

The differences follow a logic. ChatGPT rewards being a clear, established business: one the wider web describes the same way in several places, with a plain factual profile it can quote. Because it reads Bing, your presence in Bing's local results matters more than most owners expect. Google's AI answers reward what strong Google rankings always have: a complete Google Business Profile, real reviews, fast and clear pages, and obvious local relevance. None of it is exotic. ChatGPT and Google each have a house style for the sources they trust.

The good news if you run a local shop

For a homeowner asking an assistant who to call for a burst pipe or a water heater, the picture is friendlier than those overlap numbers suggest. Local recommendations lean on a shared foundation every assistant respects: your Google Business Profile, your reviews, the directories that list your name and number, your license, and the service pages on your own site. Research that separated the sources engines cite from the businesses they actually name found the named businesses overlapped far more than the underlying sources did. In plain terms: you do not need a separate company for each assistant. Get the shared trust signals solid, and the per-assistant quirks become small adjustments instead of separate projects.

Why it is never one and done

The catch is that none of it holds still. The assistants keep changing what they pull from and how they weigh it. Google keeps changing how local results work. Your competitors keep earning reviews and adding pages. A profile that looked current in spring reads as stale by fall if nothing new has happened on it. A one-time cleanup helps for a while, then drifts. Staying recommended is maintenance, the same way a stocked truck and a full schedule are maintenance. It is not a thing you finish.

What actually moves all of them

The work that lifts every assistant at once is the unglamorous part. Claim and reconcile your directory profiles so your name, phone, and hours match everywhere. Put your license number, with the issuing state, on your website and your Google profile. Ask happy customers for reviews that name the job and the town, not just "great service." Write service pages that say plainly what you do and where you do it. Then test yourself in more than one assistant, because, as we have seen, they will not agree.

Our ten-minute self-check walks through how to test your own company across the major assistants and read what comes back.