When we take over a Google Ads account for a local business, the first thing we open is the search terms report. It lists the actual phrases people typed before they clicked your ad. In nearly every account, a chunk of the budget has been going to searches that could never have become a customer.
A roofing company paying for "roofing jobs near me". A dental clinic paying for "dental hygienist salary Ontario". A landscaper paying for "landscaping ideas pinterest". A plumber paying for "plumber jokes". These are real examples, and none of them are unusual.
Why it happens
Google matches your keywords loosely by default, and it has gotten looser every year. If you bid on "roof repair", your ad can show for "DIY roof repair video", "roof repair job posting" and "roof repair cost calculator". Google calls this helpful. For a business that wants calls from homeowners with a leaking roof, it is a leak of a different kind.
What a negative keyword does
A negative keyword tells Google never to show your ad for searches that contain it. Add "jobs", "salary", "hiring" and "careers" and you stop paying for job seekers. Add "DIY", "how to" and "video" and you stop paying for people who want to do it themselves. Add "free" and "cheap" if those are not your customers. Add the names of cities you don't serve.
It takes about an hour to go through a few months of search terms and build the first list. After that it is a ten-minute check every couple of weeks.
What changes
The budget does not go down. It goes to better searches. In most accounts we see the cost per lead drop noticeably within a month of a proper negative list, with no other changes. It is the highest-return hour in Google Ads, and it is almost always skipped because it is unglamorous.
A starting list for most local service businesses
Treat this as a checklist to review, not a list to paste in. Every one of these is wrong for somebody: a video production company wants "video", a used-equipment dealer wants "used", and some businesses do well bidding on competitor names.
- Employment words: jobs, hiring, careers, salary, apprentice, training, course
- Do-it-yourself words: DIY, how to, tutorial, video, youtube, manual
- Research words: wikipedia, definition, meaning, history
- Bargain words that don't fit your business: free, cheap, used, rental
- Places you don't go: every nearby city you don't serve
- Your competitors' names, unless you are deliberately bidding on them
Then add your own, from your own search terms. Every business has a handful of words that keep showing up and never turn into a call.
One warning
Don't go too far. A negative keyword that is too broad can block real customers. "Repair" as a negative will stop "furnace repair". Review the list, keep it specific, and check the search terms report after any big change. Done carefully, this is the easiest money you will ever save.