About installing a septic tank

Installation of a septic tank

When switching to a "consolidated treatment septic tank" where it is necessary to newly set up (change) the septic tank, and can process from "single treatment septic tank" which treats only soil to domestic miscellaneous wastewater such as kitchen drainage, the septic tank It is necessary to submit documents concerning the setting of
  • When installing on a building that requires building application confirmation by new construction work and extension and renovation work, it will be handled under the Building Standard Law and related to the "Design Review Summary for Septic Tank Confirmation Application (Installation Notification)" in the Building Confirmation Application Form Attachment of documents is required.

Documents and drawings required for installing a septic tank

3 parts of each seven parts of the septic tank design outline (installation notice form) "for specific administrative agencies, for municipalities and installers" and up to ten days before the start of construction (up to 17 days in case of town assistance) Please submit it to.
  • When setting up a septic tank other than the certified septic tank, please submit it until 3 weeks before construction starts (up to one month in case of town assistance).


  • Septic tank confirmation application (plan notification) Design outline
  • Septic tank installation notification form
  • Septic tank registry
  • Septic tank certificate
  • Structural drawing
  • Nearby sketch map
  • layout drawing
(Those that understand the arrangement of the building and the septic tank, those that understand the connection from the septic tank)
  • Plans of buildings
  • Area table of building
  • Other required documents
(Checklist for calculating the minimum number of people to process when installing in existing houses, consent form, etc.)

In case of osmotic release

When permeating septic tank treated water underground, the installer must confirm that there is no hindrance on environmental preservation even if it permeates and releases. In case of penetration discharge, please submit 3 copies of each of the following documents in addition to the above documents.


  • Underground penetration discharge system outline etc.
  • Calculation formula for penetration area
  • Penetration test photos (about 3 places)

About discharge destination of septic tank treated water

Regarding the treated water of the septic tank, in principle, thank you for penetration underground in the premises. In the case where it is difficult to process underground infiltration method, it is necessary to discuss with the administrator of the release destination in advance whether there is no hindrance to the road side grooves, rivers and the like without trouble and whether the reverse flow due to insufficient inclination etc etc. Also, if agricultural water is flowing in the side grooves to be discharged, it is also necessary to discuss with the manager etc.

Merger treatment septic tank maintenance project subsidy

We are engaged in merger treatment septic tank installation maintenance project with the aim of promoting the installation of merger treatment septic tank for areas that are not maintained such as sewers, to prevent pollution of public waters, conservation of living environment and improvement of public health I will. For details, please visit the townspeople's life page.

Link to the septic tank

For other details about the septic tank, please see the following page.

Inquiries regarding information on this page

City Construction Division Architects
Living Environment Division, Town Community Living Section