Japan Water Cost is a free, English-language tool for foreign residents deciding how to drink their water in Japan: straight from the tap, bottled, or from a rented water server (ウォーターサーバー). It compares the real monthly cost of all three for your household — including the one figure servers keep off the front page, the 解約金 (cancellation fee).
Why we tell most people to drink the tap
Most new arrivals buy bottled water because nobody told them the tap is safe. It is: Japanese tap water meets 51 legally enforced quality standards. For the large majority of households, tap water — with a kettle, or a filter if you prefer the taste — is both the cheapest and a perfectly safe option. Saying so plainly is the whole point of this site. We earn your trust on the majority we save money for, and we only point to water servers for the minority who genuinely benefit: heavy hot-drink users, baby-formula households, offices, and people who can't carry water home.
How we source the numbers
The tap-safety facts follow the 水道法 (Water Supply Act) water-quality standards and the published hardness data. Municipal water unit prices come from utility schedules (Tokyo, Osaka); bottled prices from current shelf surveys; server pricing, minimum terms, and 解約金 schedules from operator pages and market data. Everything is given as a researched range, because prices vary by region, retailer, and provider — and provider figures are re-checked against their own pages.
Where we make money, and where we don't
The tap-safety information, the hardness explainer, and the cost comparison carry no commercial links. When we do show water-server options, they appear only in the server section — and we state the minimum contract term and the 解約金 right next to the link, because that's the honest thing to do. This is an independent project, not affiliated with any water utility, bottler, or server company, and it is informational only, not professional advice. Confirm current figures before you commit.
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