How to choose water for tea

Start with drinking water that smells fresh and has no distinctly salty taste. If you like the tea it makes, keep using it. Mineral content affects flavour, but the best water depends on the tea and your taste, rather than one ideal TDS reading.

Boiling water in a glass electric kettle.
Photo: Plorpy2 · CC BY-SA 4.0

Compare the taste first

Brew two fresh portions of a familiar tea: one with your usual water and one with still water that has a lower mineral content. Keep leaf weight, water volume, temperature, and time the same. Taste after cooling slightly. A paler infusion is not necessarily better; compare aroma, strength, and aftertaste.

Understand mineral content, hardness and alkalinity

TDS estimates the total amount of dissolved substances. Hardness mainly concerns calcium and magnesium. Alkalinity describes the water’s capacity to neutralise acids, often due to bicarbonates. These are different measurements: two waters with the same TDS can produce different tea.

Hard water can encourage a surface film, while high alkalinity can change colour and flavour. Water can still make good tea even if it contains calcium or leaves scale in the kettle. Check the bottle’s analysis or your water supplier’s report rather than relying on one number.

Match the filter to the problem

Activated carbon can reduce chlorine odour; reducing hardness requires suitable ion-exchange material or another appropriate process. Some filter jugs combine technologies. Check the specific cartridge’s claims and replace it as instructed. For chloramine, look for a stated reduction claim: ordinary boiling is not a reliable solution.

Reverse osmosis greatly reduces many dissolved salts. The resulting water can work for tea. If you dislike the flavour, compare it with another drinking water; there is no universal 1:10 blending recipe.

Heat the amount you need

You can reheat drinking water that has cooled. Reboiling alone does not make it “dead” or guarantee flat-tasting tea. There is little reason to keep boiling it away: evaporation increases the concentration of substances left dissolved. Keep the kettle clean and descale it according to its instructions.

Questions and answers

Can I use tap water?

Yes, if it is safe to drink and you like the tea it makes. A filter may help with a specific issue, such as an unwanted smell or hardness.

What TDS should tea water have?

There is no universal target. A household meter estimates TDS from conductivity; it does not identify the salts or establish whether water is safe.

Can I use reverse-osmosis or distilled water?

Water intended for drinking can work. Minerals affect flavour and extraction, but low mineral content does not necessarily make tea taste bland. Do not use water sold for technical or appliance use.

Do I need expensive spring water?

No. A source name or a high price does not guarantee better tea. Start by comparing two readily available drinking waters.