Excavation and temporary use of public sewers

1. When we perform the following drainage including drainage for construction, and use public sewer temporarily, please submit public sewer temporary use permission application and receive permission of Public Works Office. （Yokohama City Sewerage Ordinance, Article 17, Paragraph 3）
   • （１） Spring water, rainwater, drainage for construction work, etc.
     (For spring water and rainwater, when a pot is provided with a pot)
   • （２） Wastewater from temporary toilets and hand-washing areas installed in temporary offices.
   • （３） Accumulated water from caretaker holes such as telephones, electricity, gas, etc.
   • （４） Wastewater associated with other construction work.

   In addition, when applying, the drainage method etc. must conform to the attached standards. In addition, industrial waste cannot be drained.

2. When digging near the public sewer for civil engineering or construction work, or if you are going to dig deeper than drain pipe, please submit a registration form digging near the public sewer. （Yokohama City Sewerage Ordinance, Article 25）
3. Drainage method
   • （１） When discharging in a confluential area, flow directly into the connection basin.
   • （２） When discharging in a diverted area, the flow directly into the sewage connection basin.
   • （３） Drainage associated with construction on the road (including underground) can be connected to a human hole by installing a mounting pipe. However, please consult with Public Works Office regarding the connection location, construction method and restoration method.
   • （４） If there is no connection basin on the premises or near the site, apply for self-financing construction to Public Works Office, install the connection basin and mounting pipe, and submit a temporary application form.
4. Structure of drainage facilities
   When discharging wastewater for construction, install drainage facilities as follows. (excluding temporary office wastewater and temporary toilet drainage)
   • （１） Public sewerage facilities, road facilities, etc., and traffic.
   • （２） In the drainage facility, install a sedimentation tank that meets the following standards.
     Oh, a rectifier plate, cough, etc., so that it does not cause disturbance by running water.
     B. The sedimentation tank has a structure of two or more tanks
     C In principle, the average flow velocity is 0.3 m/s or less.
     D. In principle, stay time is 30 seconds or more.
     The muddy water is 60cm or more
   • （３） When discharging alkaline or acidic sewage, set up a neutralization tank and adjust it before discharging. The neutralization tank must have a function to automatically stop the power pump when the water quality exceeds the standard value in principle.
   • （４） The sedimentation tank shall have a structure in which the flow rate can be measured in principle.
5. Water quality standards and drainage volume certification
   • （１） Water quality such as drainage for construction is based on the regulations concerning conservation of Yokohama City living environment and standards such as the Yokohama City Sewerage Ordinance, in addition to those listed in the following table. Water quality should be inspected from time to time, and appropriate management should be performed to comply with laws and regulations.

     Water quality standards and drainage volume certification

     Items	Processing area (From flowing into the sewage treatment plant)	Untreated area (It does not flow into the sewage treatment plant)
     Hydrogen ion concentration	PH5 and less than 9	HP5.8 or higher 8.6 or less
     Suspended Substances Bentonite Other earth and sand	Less than 600 ppm	70 ppm or less

   • （２） The certification of the amount of drainage and the adjustment of sewerage usage fee will be performed by the Environmental Planning Bureau Accounting Division Sewerage Fee (telephone 671-2826). Please pay sewerage system usage fee by delivery letter of advice that Motoichi issues.
   • （３） When we violate laws and ordinances or the above standards and permission conditions, or when the city deems it necessary, we may remodel, relocate or remove drainage facilities. The expenses required in this case shall be borne by applicant.
6. If the pipeline is blocked or damaged due to effluent such as construction drainage, restoration work costs for the facility will be collected. However, if there is an application for self-financing construction from the cause, the cause person to carry out restoration work.
7. Please apply for permission and notification procedures as follows.

   About permission application and procedure

   Application documents	Number of copies	Date of submission	Submission address
   Public sewer temporary use permission application	3 copies	7 days prior to release	Public Works Office
   registration form digs near public sewers	2nd section	7 days before dug	Public Works Office

8. Contact information

   Contact list

   Contact information	Phone number	Details of inquiry
   Environmental Planning Bureau Accounting Section Sewerage Fee	671-2826	Report on drainage volume and inquiries about sewerage usage fees
   Environmental Planning Bureau Sewer Management Division Sewerage Management	671-2842	Viewing the sewer ledger map attached to the application form and registration form
   Environmental Planning Bureau Water and Soil Environment Division	671-2489	Water quality standards for public water bodies
   Resources and Waste Recycling Bureau Industrial Waste Management Section Emission Guidance Section	671-2513	Industrial waste
   Public Works Office, where the site is located	Please check it from the link.	Inquiries other than the above

(Reference)　Yokohama City Sewerage Ordinance

• Article 17, Paragraph 3
  (Notification of start of use, etc.)
  Regardless of the provisions of the preceding two paragraphs, those who intend to use the public sewer by eliminating the sewage associated with civil engineering, construction work, etc., and those who intend to use the public sewer temporarily must obtain the permission of the mayor in advance. No.
• Article 25
  (Digging in the vicinity of public sewers)
  Person who is going to perform construction to dig deeper than buried position of the drainage sewer pipe near drainage pipe of public sewer must notify the mayor beforehand according to rule by rule.
  2 The mayor may order necessary measures to the person performing the construction set forth in the preceding paragraph to the extent necessary to maintain the function and structure of the drainage sewer of the public sewer.