In a leak or overflow situation, panic hits fast. If you only know where the main building valve is (or not even that), you may end up switching off water for the entire house or building when only one tap or toilet is the problem.
Most modern setups have smaller isolation valves—under basins, behind toilets, near geysers. If a plumber, while installing or repairing, walks you through “Yeh valve band karoge toh sirf yeh line band hogi,” you gain control.
In future, if a particular tap fails, you can calmly shut just that part and carry on with life while waiting for repairs, instead of living without any water.
