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Water solutions for your home espresso machine

water solutions for your home espresso machine

before your first cup, test the water

When it comes to espresso, water quality is crucial, and not only to how good your coffee will taste. The wrong water could cause your machine to break down, lead to higher maintenance costs, and shorten its lifespan.

What is “the wrong water”? Well, it comes down to its mineral content and chemistry, which can vary massively depending on your location and water source. Generally, mains supply water in the United Kingdom is 100% safe to drink, and tastes pretty good, but that alone doesn’t make it ok to use in your espresso machine.

Water with too much mineral content is very likely to deposit limescale, which will inevitably cause problems – usually a blockage, and probably a repair bill.

At the other end of the spectrum, water with low mineral content, low pH, or high chloride content can be so corrosive (at high temperatures and pressure) that it rapidly degrades components inside the machine. Water that is very pure, like distilled or rainwater, has this corrosive effect, and sometimes won’t work with the machine’s sensors, in which case it won’t fill or heat up.

Surprisingly, even water from common drinking-water filters is often unsuitable, as they have little effect on the mineral content or underlying chemistry – happily, many espresso-machine-specific filtration and treatment products do exist, the key is choosing the right one for your particular source, which leads us to testing.

We recommend using the water testing kit that comes with your new La Marzocco before you use the machine. Visit our online Water Calculator to interpret the test results. Please don’t hesitate to contact us for help, we have many good water solutions, and we’re happy to guide you.


For optimum machine performance, the water properties should fall within the following parameters:

value units min. max
T.D.S ppm 90 150
Total Hardness ppm 70 100
Total Iron ppm 0.0 0.02
Free Chlorine ppm 0.0 0..05
Total Chlorine ppm 0.0 0.1
pH 6.5 8
Alkalinity ppm 40 80
Chloride ppm 0 30

water testing tips

Always use cold water from either the tap, filtration cartridge or bottle – do not test hot water or water from the machine.

Once you have tested the water, you can enter the results in the La Marzocco Water Calculator.

If you choose to use bottled water for your machine, check that the required minerals are present. Water with a low mineral count, or distilled water, will not be recognised or accepted by the machine causing the blue water light to flash even when the reservoir is full.