Most PPC playbooks assume a buyer who browses, compares and eventually fills out a form. Plumbing breaks that pattern. A large share of your valuable searches come from people standing next to a leaking supply line, a backed up toilet or a water heater that just gave out. They do not want a landing page tour. They want to know whether a real person answers, whether you serve their street and how soon a truck can arrive.
Two kinds of intent inside one trade
Next to those urgent searches sit slower ones: repiping an older house, moving to a tankless unit, adding a bathroom, replacing a sewer lateral after a camera inspection. These homeowners read reviews, ask about permits and often call several shops. When an account lumps both kinds of search into a single campaign, Google tends to spend where clicks are easiest, which is rarely where your margin lives.
Clicks from people who will never hire you
The word plumber pulls in apprentices looking for work, students checking licensing rules, do it yourselfers searching for a part number and shoppers hunting for fixtures at a big box store. Without a careful negative keyword list, a noticeable slice of your spend answers questions that have nothing to do with a service visit.