Plumbing in connects the machine directly to the mains water supply instead of a refillable tank.
The case for plumbing in
No refilling, which matters at café volumes. Line pressure pre-infusion, on machines that use it. Direct drainage, so no drip tray to empty. Rotary pumps, which are quieter and more durable, usually require it.
The case against
You lose control of the water. A tank lets you use filtered, bottled or recipe water, chosen for both taste and machine longevity. Plumbed in, you get whatever comes out of the tap unless you install a proper filtration system.
For a home user in a hard-water area, this is a serious argument.
Installation. A tap, a pressure regulator, a drain connection, and often a plumber.
The machine cannot move.
The middle ground
Many prosumer machines are convertible — tank by default, plumbable later. That is the sensible choice if you are unsure.
The filtration issue
If you plumb in, install proper filtration: a softener cartridge or a reverse osmosis system with remineralisation.
Plumbing a machine straight into hard mains water will destroy it, and it will take a year or two.
The honest answer for most homes
Stay on the tank. Use filtered or recipe water. Refilling once a day is not a hardship, and the control over water quality is worth more than the convenience.
Last reviewed 8 August 2026