What water for tea? Tap, filtered or bottled
Why water changes the taste of tea, what hard water is, whether a filter is worth it, which bottled water to choose and why you shouldn't boil it more than once.
2 min read, 18 October 2026
An infusion is almost entirely water. The same sencha brewed in two different waters can taste like two different teas. The good news: you don't need special water, just a few simple rules.
Hard water takes away flavour
In many parts of Poland tap water is hard: it contains a lot of calcium and magnesium. That isn't harmful, but you can see and taste the effects in tea:
- a dull film forms on the surface of the infusion
- the infusion darkens and turns cloudy
- the aroma is flat and the taste more astringent
- the kettle quickly furs up with limescale
Japanese teas are made in a country where the water is usually very soft, and it's in soft water that they taste best.
Filtered water
The simplest solution is a filter jug. A filter reduces hardness and removes the smell of chlorine. Change the cartridge as often as the manufacturer recommends: a used-up one stops working.
Bottled water
If you buy water for tea, look on the label for low-mineral water: total mineralisation up to about 100–150 mg/l. Water with a lot of calcium, magnesium and bicarbonates, fine as it is for drinking, will have the same effect in tea as hard tap water.
Avoid distilled and demineralised water. With no minerals at all, the infusion tastes empty and flat.
Fresh water, boiled once
- Fill the kettle with fresh water, not water that has been sitting in it since the morning.
- Don't boil water several times. Reboiling drives out what's left of the dissolved air and concentrates the minerals, and the infusion turns flat.
- For green teas you don't need to boil the water. It's enough to heat it to the temperature you need. If your kettle has no temperature control, boil the water and wait a few minutes, or pour it into a cup and back into the jug. Each pour lowers the temperature by a few degrees.
A simple test
Brew the same tea in tap water and in filtered or low-mineral bottled water. Ideally a delicate green tea, such as sencha or gyokuro. You'll see the difference in the colour before you even taste it.
You'll find the temperature and time for each of our teas in the brewing guide. The most sensitive to water are Gyokuro Uji and Sencha Kagoshima.
