Which is why I can't legally replace my water heater - a simple job that I've done myself several times in other cities. Or lots of other basic home maintenance. (I grew up in a house built by a plumber, and my current house was owned by a builder before me - so I have plenty of first hand experience with how bad trades can do their own work)

That’s horrible that you legally cannot replace your own water heater. What region mandates that?

Where I live I can replace my own water heater, but it’s more cost-effective not to because the most reliable brands will only sell to licensed plumbers. So I can get a big box store model that will leak or die in 3 years for $300, and then have to pay for fittings, wiring, etc. myself and pay to dispose of the old one and provide my own labor, or pay a plumber buddy of mine who has access to the good stuff that will last 10-15 years $1000 to install one for me.

Building permits and inspections make sense in a lot of cases for things that could cause societal damage. E.g. if I wire my house wrong and it burns down, it could kill the people living in it (even if it’s not me) or set my neighbor’s house on fire. If I put in a septic system wrong it could poison all the wells in the area. But when you start needing permit and inspections for basic maintenance, it becomes difficult to justify the regulations.