What machine makers say about water in their manuals

There's no single rule. Water advice sits in each maker's own manual or support pages, and two makers can say close to opposite things. Breville says its recommendations can vary by machine and local water hardness¹.

Two makers are covered here, and your machine may be neither. Use this page to learn what kinds of statements to look for, then read your own manual.

What a water section usually names

Look for four things in the manual:

• A water type to use, such as tap, filtered, bottled or another.
• A water type to avoid.
• A hardness or TDS limit, and the unit it's written in.
• A hardness setting or test strip, if the machine has one.

Units are sorted out in this explainer on hardness numbers.

Breville

Breville's support article says tap water may work well for some machines and water hardness levels. For others it names alternatives: filtered water, bottled spring water or mineral water¹. Some models recommend changing to another water source when the measured hardness is particularly high¹.

It also lists what to avoid: distilled water, demineralized water, and heavily filtered water that removes nearly all minerals¹. Its reason is that water with little or no mineral content may affect taste and how the machine is designed to operate¹.

Reverse osmosis (RO) water gets its own entry. Breville says to avoid RO water if filtering removes nearly all the minerals. For applicable models, RO water may be suitable if some minerals have been added back. It tells you to follow the water recommendations in the manual for your specific machine¹.

The article ends with a plain habit. Use fresh, cold water when filling the tank¹. Its blog suggests filtered or reverse-osmosis water with a moderate mineral content to help prevent mineral buildup².

Decent Espresso

Decent Espresso takes the opposite view for its DE1 and Bengle machines. It says they're designed to safely use unremineralized reverse osmosis or distilled water³.

It still has conditions. Any tap water should be filtered before use in the machine, it says³. If you add minerals to water going in, it asks you not to use chlorides, because chloride raises corrosion risk³. It suggests keeping chloride under 10 ppm in treated tap water³.

Side by side

Why they differ

Neither maker gives one shared reason. Decent points to its small tubes and calibrated pressure-restricting orifices, where avoiding scale is particularly important³. Breville points to taste and to how the machine is designed to operate¹. Each statement is about that maker's own machines.

Where to check

Look in the printed manual, the maker's website support section, or the sheet in the box. If the manual and a web article disagree, the manual for your model wins. If you can't find the water section, ask the maker. And don't change anything inside the machine to suit a water type. That's outside what this site covers.

More on the types themselves is on the page about tap, filtered, bottled and softened water.