Do I need filtered water for pour-over?

There is no machine at risk here, so unlike espresso this is entirely a taste question. It is still worth doing.

Chlorine

The clearest gain. Municipal water is chlorinated or chloraminated, and both are perceptible in coffee at concentrations far below what you would notice drinking the water plain. They flatten aromatics and add a faint pool-like edge.

Any carbon filter removes them, and the difference in a light-roast filter brew is obvious side by side.

Hardness

Very hard water dulls acidity and mutes the brighter notes. Reducing it brings definition back.

There is a floor: strip too much and extraction suffers, because magnesium and calcium actively help pull flavour into solution. Very soft water makes hollow coffee.

What that means

Filter, and do not over-filter. A standard jug filter is right for most people. A mineralising cartridge — one that removes hardness and adds magnesium back — is a genuine step up for filter brewing specifically.

Where you will notice it most

Light roasts, washed coffees, and anything you are drinking black and paying attention to. In a dark-roast French press with milk, considerably less.

The kettle test

If your kettle furs up, your water is hard enough that filtering will change the cup.