Guide

Best Water for Espresso: Hardness, TDS & Why It Matters

Espresso is about 90% water — so the water you use shapes both the flavour in your cup and the scale in your machine. Here is what to use.

By Julien A. · Updated June 2026

Why water is most of your coffee

A shot of espresso is roughly 90% water, and the minerals dissolved in it both carry flavour and cause limescale. Too few minerals and extraction goes flat and sour; too many (especially the wrong ones) and you get dull coffee plus rapid scale build-up. Getting water right is one of the cheapest upgrades to your espresso.

The target

Total dissolved solids (TDS): roughly 75–150 ppm
Some calcium/magnesium for good extraction (they bind flavour compounds)
Low bicarbonate / alkalinity — high alkalinity dulls acidity and accelerates scale
Near-neutral pH

What to use

✅ Filtered tap water (a carbon filter) — fine for most people and machines
✅ Remineralised water or 'third-wave water' mineral packs — for full control
✅ A bottled spring water that falls in the right hardness range
❌ Distilled / pure RO water alone — too empty, gives flat extraction and can corrode boilers
❌ Very hard tap water — chalky taste and fast scale build-up

If your water is hard

Either filter or remineralise it, and descale more often to stay ahead of build-up. Soft, balanced water is the single best way to reduce how frequently you need to descale — see our descaling guide for the routine.

Watch it done

▶ Watch video tutorials on YouTube

FAQ

Can I use distilled water for espresso?

Not on its own — it is too 'empty' to extract well and can be corrosive to boilers. If you start from distilled or RO water, add a remineralisation pack to bring it into range.

What is the best water for espresso?

Filtered tap water suits most setups; for full control, remineralised water or a coffee-specific mineral pack hitting ~75–150 ppm TDS with low alkalinity is ideal.

Does water type really affect scale?

Yes — hard, high-mineral water leaves limescale much faster, which is why soft/filtered water both tastes better and means less frequent descaling.

Recommended gear

Putting this into practice? Browse our espresso machine reviews and grinder reviews — or start with the Breville Barista Express, our pick for most home baristas.