You checked your phone, searched your service and your town, and you were third instead of first. Last week you were first.
The instinct is that something is wrong, possibly something you did. Usually neither is true, and the reason is a fact about local search that almost nobody explains properly.
You do not have a ranking
This is the thing to understand before any of the rest matters.
In local search, proximity between the searcher and the business is one of the heaviest factors. Which means your position is not a property of your business. It is a property of where the person searching happens to be standing.
A plumber in the centre of town might rank first for somebody two streets away, fourth for somebody across town, and nowhere at all for somebody at the far edge of the service area. All at the same moment, with nothing having changed.
So "my ranking moved" is usually comparing two different questions. Checking from your office tells you how you rank at your office. It tells you very little about the town fifteen minutes away where half your work comes from.
If you want to know what is actually happening, check from several points across your service area, or use a tool that reports a grid rather than a single position. The picture is almost always more varied than owners expect.
The other reasons it moves
Once you have accounted for proximity, several genuine causes remain.
Personalisation and history. Search results are shaped by the searcher's previous behaviour and signed-in state. Checking your own ranking while signed into an account that has visited your own website repeatedly is close to useless. Use an incognito window at minimum.
Normal fluctuation. Local results churn constantly and small movements are simply noise. A position drifting between second and fourth across a week is not a trend.
Google updates. Core updates and local algorithm changes roll out regularly and can shift results for everybody in a category at once. If every competitor moved as well, that is the likely cause and there is nothing to fix.
Competitors doing something. Somebody else filled in their services section, gathered fifteen reviews, or added a category. Your position can fall without you changing anything, because relative position is relative.
Something you changed. Edits to your primary category, business name, hours, or address all affect ranking. So does inconsistency between your Google profile and your listings elsewhere. If the drop coincides with a change you made, start there.
Review velocity. Recency matters, not just volume. A business that collected thirty reviews two years ago and none since is losing ground to one collecting two a month, and that happens gradually enough to look like an algorithm change.
Seasonal competition. In a trade where demand swings enormously, the competitive set changes with the season. More businesses bid, post, and chase reviews during the peak, which can move you without anything about you having changed.
How to diagnose it properly
Four checks, in order, and most of them take minutes.
Check from multiple locations, incognito. Before anything else. A large share of reported ranking drops disappear at this step.
Check whether competitors moved too. If the whole result set reshuffled, it is an update rather than you.
Check your own recent edits. Category changes, name changes, hours, a new address. Look at what you changed in the fortnight before the drop.
Check your review recency, not your total. When was the last one.
If all four come back clean and the drop persists across weeks rather than days, then it is worth investigating properly. If it moved on Tuesday and you are checking on Wednesday, wait.
The thing that matters more than the position
Rankings are a means, and the end is enquiries.
It is entirely possible to drop a position and receive more calls, because position two with fourteen recent reviews and photographs of real work outperforms position one with four reviews and no images. And it is possible to hold position one while calls fall, because a competitor started publishing prices and you did not.
So the number worth watching is not your rank. It is calls and messages from your Google Business Profile, and enquiries overall. Those are in your profile insights and in your own records, and they are what the ranking was supposed to be a proxy for.
If rankings dipped and enquiries held steady, nothing happened that matters.
What to do about a real drop
Assuming the diagnosis holds and it is genuinely persistent, the responses are unglamorous and they are the same things that would have helped anyway.
Fill the services section properly, taking the pre-defined options first. Confirm your primary category is the most specific accurate one. Get recent reviews flowing again. Add photographs. Make sure your name, address, and phone match everywhere they appear.
None of that is a recovery tactic. It is the underlying work, and a ranking drop is frequently just the first time somebody notices it has been neglected.
The reframe
Checking your ranking is a habit that feels like monitoring and is mostly anxiety. It moves constantly, it differs for every person searching, and it is heavily influenced by where they are standing.
Check it monthly, from a few points across your service area, in an incognito window, and write down what you saw so the next check is a comparison rather than a reaction.
Then spend the attention you saved on the enquiry count, which is the thing you were actually trying to measure.