System of sewerage and drainage facilities

Role and structure of sewerage (link to Sewerage and Rivers Bureau page) (outside site)

Drainage facilities are facilities such as drainage pipes for draining sewage from kitchens and toilets and rainwater that has fallen on the premises to sewer pipes. The maintenance will be done by everyone.
Drainage facilities have the following differences depending on whether the connecting sewer is merged or diverted.

It is a method of combining sewage and rainwater into the sewer with a single drain pipe.

This is a method of dividing sewage and rainwater into sewage pipes and rainwater pipes in the sewer, respectively. Do not drain sewage into rainwater pipes.
In addition, rainwater may flow into U-shaped ditch.

Areas where sewers have been maintained and sewage can be treated at sewage treatment plants are called "treatment areas." Those who own buildings in the treatment area are required to wash water.
Washing work refers to the following work.

Installation of drainage facilities for draining water from toilets and kitchens into the sewer must be done without delay after it becomes a treatment area. (Article 10 of the Sewerage Law)
If the sewer is diverted, the drainage system must have a structure in which the sewage is divided into sewage and rainwater and drained to the sewer. (Article 8 of the Sewerage Enforcement Order)

The toilet must be converted to a flush toilet within three years of becoming a treatment area. (Article 11-3 of the Sewerage Law)

If a septic tank is used even in a flush toilet, the septic tank must be abolished within three years after it becomes a treatment area. (Article 15 of the Yokohama City Sewerage Ordinance)
In addition, when we abolish septic tank, we must submit septic tank abolition report within 30 days. (Article 11-2 of the Septic Tanks Act)
After abolishing the function of the septic tank and cleaning and disinfecting, we will do it in the following two ways.