Sort the work by whether water is escaping, not by what kind of pipe it is
Urgency is the axis that actually separates plumbing searches, and it decides everything about the page that should meet them.
A person watching water spread across a floor has no patience at all. They want a number that gets answered and somebody who can come now. Reading is not part of what is happening.
A person with a slow drain, a water heater that has stopped working or a toilet that will not stop running has some patience. They will compare two or three companies, look at pricing and reviews, and decide within a day or two.
A person considering a repipe, a sewer line or a water treatment system has weeks. They will read, get quotes, talk to a spouse and possibly get a second opinion on whether the work is needed at all.
Most plumbing sites organize by service instead, which puts a drain cleaning page and a whole house repipe page in the same list with the same shape. The visitor arriving with a flooded laundry room and the one planning a repipe get identical treatment, and neither is served well.
Sorting by urgency also tells you where to put effort. The flooding page needs to be fast and short. The replacement page needs to be genuinely thorough, because it is going to be read against competitors rather than skimmed.