Water filtration for cafés
Water is about 98% of a cup of coffee, so its chemistry is not a side issue for a café — it is an ingredient. But the reason most cafés fit filtration is more prosaic: scale destroys espresso machines, and espresso machines are expensive.
In a hard water area, an unprotected commercial machine will develop scale in the boiler, the heat exchanger and the group head. The failures that follow are expensive, and they happen mid-service.
What a café actually needs
Scale protection for the machine. Non-negotiable in a hard water area, and usually a manufacturer warranty condition. Depending on hardness this is either a softening cartridge, an ion-exchange unit sized to the machine, or a small commercial softener.
Carbon filtration for taste. Chlorine is disastrous in coffee — it strips the aromatics that the whole extraction is trying to preserve. Every commercial coffee filtration cartridge includes a carbon stage for this reason.
Sediment pre-filtration. Protects everything downstream and costs almost nothing.
Not, usually, reverse osmosis. RO strips the minerals that extraction actually relies on, and coffee made with pure water tastes flat and hollow. Where RO is used in specialist settings, it is followed by controlled remineralisation. That is a deliberate technical choice, not a default.
The number that matters
Coffee people talk about total hardness and alkalinity as two separate figures, and both matter for different reasons. Hardness affects extraction and scale; alkalinity buffers acidity and affects how the cup tastes.
Water treated only to remove hardness while leaving alkalinity high produces flat, dull coffee. This is why a domestic softener is not automatically the right answer for a café even though it fixes the scale problem.
If coffee quality genuinely matters to your business, this is worth taking specific advice on from a commercial water specialist rather than a general plumber. If your priority is simply keeping the machine alive, standard commercial filtration will do that.
Sizing and servicing
Commercial cartridges are rated in litres, and the rating assumes a hardness figure. A cartridge rated for 6,000 litres at moderate hardness will deliver far less in Kent than in Manchester.
Fit a flow meter. It turns cartridge replacement from guesswork into a measurement, and on a busy site it will show you that you are getting through capacity considerably faster than the calendar suggests.
Put the servicing on a contract. A café cannot afford to discover a spent cartridge by tasting it.
Records and compliance
There is no regulation requiring a café to filter its water. What there is: water used in food and drink preparation must be wholesome, and your food safety management system needs to demonstrate how you ensure that.
Where you have filtration, its maintenance is part of those records. Dated service records, cartridge change logs and the specification of what is fitted are what an environmental health inspection will want to see.
'We change it when the coffee tastes off' is not a documented procedure. Keep the paperwork.