Cloudy or brown tap water in a Tokyo apartment

If your Tokyo apartment's tap water looks white or cloudy, fill a clean, clear glass with cold water and leave it standing. Watch whether it clears from the bottom upwards. If the cloudiness stays, the water is brown, or you notice an unfamiliar smell or particles, use another source of drinking water while you contact the building manager. Don't taste it to identify the problem.

White water that clears from the bottom

The Tokyo Bureau of Waterworks explains that small air bubbles can make tap water look white. As the bubbles rise, the water clears from the bottom of the glass. This can happen when a strong flow from the tap draws air into the water.

Let the glass stand without stirring it. A short video can show the change more clearly than a photo of the cloudy water alone. If it becomes clear in this way, the bureau identifies air as the cause; you don't need to buy a filter just to remove those bubbles.

White water that stays white needs a different response. The bureau says to contact its customer centre if the cloudiness does not disappear after the glass has been left standing. Describe any smell or visible particles too, even if some bubbles have cleared. The glass check helps explain the appearance; it isn't a water-quality test.

Brown or rusty-looking water

For red or brown water, the bureau's troubleshooting guidance identifies rust from pipes as a possible cause and advises running water until it clears. Water-main work or an unexpected fault can disturb rust in the pipes.

Use a cold tap for this check and stay with it. If the water doesn't clear, stop and report it rather than leaving the tap running indefinitely. Don't fill the kettle or start cooking with the discoloured water. If the building has issued instructions after maintenance or an outage, follow those and ask when normal use can resume.

Tell the manager whether the colour appears only when you first turn the tap on, keeps coming back, or remains after running it. The Tokyo Government's water-quality advice distinguishes a problem in one building's pipes from discolouration affecting nearby homes. Repeated brown water can need a pipe repair even when flushing makes it clear temporarily.

You don't need to inspect other apartments or open a plumbing cupboard. The manager can check whether other residents have reported the same problem and whether work is taking place in the building.

Why a shared water tank changes the contact

Some apartments receive water through the building's storage tank. Others connect directly to the water supply. You may not know which your temporary home uses, especially when water is included in the rent.

The water bureau's contact guidance for discoloured water separates these arrangements. For buildings with a storage tank, it recommends contacting the manager first. For a direct supply, it directs residents to the responsible water office. If you're unsure, give the rental company or manager your building address and ask which arrangement applies.

The distinction matters when further investigation is needed. The bureau's water-testing FAQ says residents can request a water-quality test through its customer centre. Testing for an apartment building with a receiving tank may instead be handled by the public health centre. Ask the manager to help arrange the appropriate contact if the cause remains unclear.

Send a description the manager can act on

Include the apartment number, the affected tap and when the change began. Say whether you used cold or hot water, whether another tap has the same problem, and what happened when you left a glass standing or ran the cold tap. Attach the photo or video rather than describing the water only as “strange.”

A useful message might be: “The kitchen cold tap has been running brown since this morning. It hasn't cleared after running it briefly. The bathroom cold tap looks normal. I've attached a photo. Could you arrange a check and tell me what water we can use while we wait?” Change those details to match what you observed.

Our apartment contact guide separates maintenance problems from situations that need emergency services. If the water itself looks normal but the smell comes from the drain, the drain-smell guide explains the separate checks for that problem.