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1. Outline of the Tokyo Tap Water Quality Check

Checking the customer’s water

Simple water leakage check

  • We will ask you to turn off all of the tap in your home, and then check for water leakage by observing the water meter.
  • We will explain the method used to determine whether leakage is present (in Japanese only).


Simple water quality check

  • For customers who request, in addition to visually inspecting the tap water, we will measure the residual chlorine concentration※1 and electrical conductivity※2 levels to check water quality.

Measuring residual chlorine concentration

Measuring electrical conductivity


Notification of results (in Japanese only)

  • Upon completion of the check, we will present the customer with a notification form containing the results.
  • We will explain the results to the customer.

Public relations and gathering public opinion

Introduction to the Bureau’s main initiatives

  • Through pamphlets and other materials, we introduce efforts made to make tap water even more delicious, as well as helpful information you should know to prepare for when a major earthquake strikes (in Japanese only).


Survey(in Japanese only)

  • We will conduct a survey to gather opinions and inquire about customer needs.
  • There are three ways to return the survey: the inspector will collect it from you at the home, by mail, or online.
  • Those who respond to the survey may be selected to win prizes in a lottery.

2. Inspectors

Staff of the Bureau of Waterworks, employees of supervised organizations or private companies with expertise in the field

3. Important notes

  1. Inspectors will wear the uniform and display one of identification cards shown below.
  2. During this check, there will be absolutely no solicitation of equipment such as water purification systems and no charge for services.
  3. Prior to conducting the check, written notifications (in Japanese only) will be distributed to notify residents in advance of the planned date of our visit.

4. Other

This fiscal year about 300,000 checks are to be conducted in an area that includes portions of the 23 special wards and 26 municipalities.

*1This measurement shows the effectiveness of chlorine which is added to tap water for disinfection purposes to protect against pathogenic bacteria, including those that cause communicable diseases. By measuring the level of concentration, we can confirm that the customer’s home is being supplied with safe, clean water.

*2This test measures the level of electric conductivity of the water sample taken to confirm that Tokyo’s safe and delicious water is reaching the customer.