How to read drawings

Sewer pipelines (drainage facilities) inside residential areas and private roads cannot be viewed because there is no material for personal property. Please check with the owner or user of the land or carry out a field survey.

Types and functions of sewer pipelines

Combined sewer systems

(Solid line) Combined sewer: Sewer in which both sanitary sewage (including miscellaneous wastewater) and stormwater both flow

Separate sewer system

(Dotted line) Sanitary sewer: Sewer in which only sanitary sewage (including miscellaneous wastewater) flows

(Broken line) Stormwater sewer: Sewer in which only stormwater flows
In separate sewer system areas, house inlets and stormwater inlets for residential drainage are necessary.

How to view the facility plan

  • In the facility plan, the upward direction shows North.
  • The arrow (←) on the sewer pipeline indicates the direction of sewage flow.
  • Information on sewer pipelines is stated between manholes.
  • Information on sewer pipelines may be displayed near the sewer pipeline or on the leader line.
  • The height of the ground and the pipe bottom is an elevation, being the height from the average sea level of Tokyo Bay (T.P.).

Embedment status of sewer pipeline

  • The height of the ground and the pipe bottom is an elevation, being the height from the average sea level of Tokyo Bay (T.P.).
  • Covering is the depth from the ground surface to the upper edge of the sewer pipeline.
  • House connection is a pipe that connects the inlet and the sewer pipeline.
    (Normally, the house connection for house inlets has an inner diameter of 15 cm, and the house connection for stormwater inlets has a diameter 20 cm.)

Types of sewer pipelines

Symbol Meaning of symbol
Combined branch line
Sanitary sewage branch line
Stormwater branch line, LU pipe, LP pipe, stormwater discharge pipe
Combined trunk line
Sanitary sewage trunk line
Stormwater trunk line, rainwater discharge trunk line, effluent conduit
Combined force main branch line
Sanitary sewage force main branch line
Stormwater force main branch line
Combined force main trunk line
Sanitary sewage force main trunk line
Sludge transportation pipe
Reclaimed wastewater recycling system (central waterworks)
Air pipe
Unknown / others
Provisional intake pipe

Sewer pipeline cross-sectional shape

Symbol Meaning of symbol
Circular
Rectangular
Horseshoe-shaped
Back split (circular)
Egg shape
LU shape
LP shape
Back split (rectangular)
Multiple section
Slipling
Trapezoid
Circular multiple (rectangular)
Circular multiple (circular)
Rectangular multiple (rectangular)
Rectangular multiple (circular)
Other cross-sections (rectangular)
Other cross-sections (circular)
Other cross-sections (rectangular / circular)
Other cross-sections (special)
Dual pipes
Construction of circular pipe invert
Construction of rectangular pipe invert

Types of manholes

Symbol Meaning of symbol
Rectangular manhole (inner dimensions 90 cm × 60 cm)
Circular manhole (inner diameter 90 cm)
Oval shape manhole (inner diameter 120 cm × 90 cm)
Circular manhole (inner diameter 120 cm)
Circular manhole (inner diameter 150 cm)
Circular manhole (inner diameter 180 cm)
Circular manhole (inner diameter 200 cm)
Circular manhole (inner diameter 220 cm)
Tokyo-original assembled rectangular manhole (inner dimensions 90 cm × 60 cm)
Tokyo-original assembled rectangular manhole (inner dimensions 120 cm × 60 cm)
Tokyo-original assembled rectangular manhole (inner dimensions 120 cm × 80 cm)
Tokyo-original assembled rectangular manhole (inner dimensions 120 cm × 90 cm)  
Assembled circular manhole (inner diameter 90 cm)
Assembled circular manhole (inner diameter 120 cm)
Assembled circular manhole (inner diameter 150 cm)
Assembled circular manhole (inner diameter 180 cm)
Assembled circular manhole (inner diameter 200 cm)
Assembled circular manhole (inner diameter 220 cm)
Symbol Meaning of symbol
Special manhole (assembled manhole)
Special manhole (inner diameter less than 90 cm)
Special manhole (inner diameter 90 cm or more)
Special manhole (with automatic sludge elutriation tank)
Diversion manhole
Manhole with tidal gate
Siphon manhole - Upstream
Siphon manhole - Intermediate
Siphon manhole - Downstream
Siphon diversion manhole - Upstream
Siphon diversion manhole - Downstream
Siphon manhole with tidal gate - Upstream
Siphon manhole with tidal gate - Downstream
inspection manhole
Double use manhole
Lamp hole
Provisional intake
Manhole with unknown shape
Flow direction adjustment part

Type of public inlet

Symbol Meaning of symbol
House inlet
Stormwater inlet (including for stormwater drainage, special stormwater inlet)
Special house inlet
Stormwater inlet (two lids) (for stormwater drainage)
Stormwater infiltration inlet (single stormwater control inlet) (for stormwater drainage)
Stormwater infiltration inlet (double stormwater control inlet) (for stormwater drainage)
Stormwater infiltration inlet (triple stormwater control inlet) (for stormwater drainage)
Small house inlet
LU / LP stormwater drainage inlet
Stormwater inlet for residential drainage
Small stormwater inlet for residential drainage
LU final special stormwater inlet (Setagaya, Ota Cities)
Stormwater inlet for residential drainage relay street inlet (Keihinjima area)
Stormwater infiltration inlet for residential drainage
Stormwater infiltration inlet (for stormwater drainage) and infiltration connecting pipe
Special inlet
House connection (same color as the inlet.)

Type of change point or junction point

Symbol Meaning of symbol
Intake port, discharge port, external pipe intake part, etc.
Wastewater treatment plant, inlet or outlet to pumping station
Underground junction point, tubular change part, etc.
Upstream part of private road intake pipe or road manager classification point
Air valve
Sluice valve
Blowoff
Inspection port (including cleaning port)

Symbols representing terrain, administrative boundaries, etc.

Symbol Meaning of symbol
Public road
Private road
River
Railway (JR)
Railway (private)
Retaining wall (slope, etc.)
Prefectural boundary
City boundary
District boundary / block  boundary

Other symbols

Symbol Meaning of symbol
Distribution (origin of left and right pipes)
Double use origin (origin of right pipe)
Secondary pipe (place where the difference in elevation between the upstream pipe and the manhole bottom is large, etc.)
Slipling (additional pipe on the outside of a pipe: measure to protect the pipe)
Transfer symbol (actual pipes overlap: congestion area)

Image of combined / separate sewer systems

Longitudinal view (schematic)

Types of manhole cover (examples)

Manholes are entrances for inspection and cleaning of sewer pipelines.

New type
Concrete type
Conventional type

Types of inlet lids (examples)

Public house inlet

Drains drainage from homes into the sewer pipeline.

House inlet
House inlet (round)
House inlet (small)

Public stormwater inlet

Drains rain that falls on the road into the sewer pipeline.

Stormwater inlet
Stormwater inlet (wire mesh)

PC site display