Why do plumbers win or lose on the first three names?
Someone with water on the floor does not compare ten plumbers. They search, look at the first few names on the map, check the stars and call. If the first number does not answer, they call the second. Local SEO for plumbers comes down to being in that short list for the localities you cover, and being the one who picks up.
Service areas, not an address
Most plumbers work from home or a small workshop and go to the customer. Google lets a business like this hide its address and list the areas it serves instead. Set those areas to where you actually go. A service area that covers the whole city looks generous, but it brings calls you cannot reach in time, and the reviews that follow.
What customers write about plumbers
In the listings we checked, the words that come up most in reviews are about speed and conduct as much as skill: quick response, arriving on time, polite staff, a fair visiting charge, and the complaints that do appear are often about behaviour or charges. That is good news, because all of these are in your control, and a reply that apologises and puts it right shows the next customer you care.
Jobs as services
Customers search for the job as often as the trade: a geyser repair, a blocked drain, a leaking tap, a new bathroom fitting, waterproofing. Listing each job as a service helps Google match you, and helps the customer see you do what they need before they call.
Summer and the monsoon
Searches for plumbers rise in the summer months, when pumps, tanks and pipes are worked hardest, and leaks follow the monsoon. Keep your hours and availability current during those weeks, since that is when a correct profile brings the most calls.