Yes—treated municipal tap water in Japan is generally safe to drink, so a glass from a suitable tap is usually cheaper than buying bottled water. Check local advisories and your building’s plumbing first. If you are tired of making barley tea at home, drinking water also removes the brewing step.
The surprise is what replaces the tea routine: a chilled water pitcher still needs washing, while bottles need carrying and recycling. Swapping the drink does not automatically remove the chore.
Is switching to tap water safe?
This comparison is about Japan, where municipal tap water is normally treated for drinking. Check your own water utility's current notices and the condition of your building's plumbing. Elsewhere, safety varies; don't assume Japanese conditions apply to your tap. If authorities warn against drinking the water, follow that warning. Boiling can kill germs, but it does not remove dangerous chemicals. After several days away, use the first water from the tap for cleaning rather than drinking. For example, Kawaguchi City advises using roughly the first 10 liters for non-drinking purposes after an absence of three days or more; follow your own water utility’s guidance.
Cooling water doesn't make it keep forever. Fill a clean, covered container from a drinkable tap, refrigerate it, and pour into a glass rather than drinking from the storage container. Replace the water regularly instead of endlessly topping it up. Tokyo's water utility advises that filtering or boiling water before storing it reduces the protective chlorine; its emergency-storage advice is not permission to leave a half-used jug in the fridge indefinitely.
How much cheaper is tap water in Japan?
Ibaraki City in Osaka Prefecture offers a concrete comparison (updated January 29, 2025). For a home using 20 m³ a month with a 20 mm meter, the water charge works out to ¥0.121 per liter. Its bottled-water example is ¥124 for two liters, or ¥62 per liter. Under those stated conditions, tap water costs about 1/512 as much. Buying that same two-liter bottle daily would cost ¥45,260 a year—and you would still have to carry the bottles home.
The ¥0.121 figure is an average within Ibaraki's stated household scenario, not a universal rate or your own bill. Base charges, usage tiers and wastewater fees vary. For context, Yokkaichi's FY2024 accounts separately report ¥185.85 in supply revenue per 1,000 liters of revenue-generating water. That is a different accounting measure, not a competing household tariff. For your actual bill, check the local water utility's tariff.
The easiest option depends on the chore
If you want to stop washing a tea pitcher, pour drinkable tap water into a glass. If you want cold water, chill it in a clean, covered container or add ice; the container still needs cleaning. Finishing a small bottle straight away can save a glass to wash. But repeatedly drinking from an open two-liter bottle can introduce microbes from your mouth into the water left inside. Japan’s Food Safety Commission recommends pouring into a glass when drinking in stages and finishing opened drinks promptly. Bottles still mean shopping, carrying and packaging waste. Count the whole chore list, not just the dishes.
Make tea when you want the taste of tea. When you just want a drink, a glass of water can clock out before the tea factory starts.
Sources: Yokkaichi FY2024 water accounts; WHO drinking-water overview; CDC water-advisory guidance.
Tokyo Waterworks: storing tap water
Japan Food Safety Commission: drinks left in bottles
Japan Digital Agency: water-supply unit revenue definition
Yokkaichi: residential water tariff
Japan National Tourism Organization: drinking water in Japan
Kawaguchi City water utility: first tap water after a long absence
Ibaraki City: tap and bottled water cost comparison
Ministry of the Environment (Japan): drinking-water quality standards
