A separate and independent building sewer shall be provided
for every building, except that where one building stands at the rear
of another on an interior lot and no private sewer is available or
can be constructed to the rear building through an adjoining alley,
court, yard or driveway, the building sewer from the front building
may be extended to the rear building and the whole considered as one
building sewer.
Old building sewers may be used in connection with a new building
only when they are found, on examination and test by the Director,
to meet all requirements of this chapter.
Sanitary sewers from building discharge to the sanitary main
in the City right-of-way shall be constructed of:
A. Polyvinyl chloride pipe (PVC) conforming to ASTM D3034 with a minimum
pipe stiffness of 46 psi at a maximum deflection of 5% and a standard
dimension ratio (SDR) of 35 or less.
B. Ductile iron pipe conforming to ASTM C151 and C110.
The size and slope of the building sewer shall be subject to
the approval of the Director, but in no event shall the diameter be
less than four inches. The slope of such four-inch pipe shall be not
less than 1/4 inch per foot. The slope of a six-inch pipe shall be
not less than 1/8 inch per foot.
Building sewers must be laid no closer than 10 feet from parallel
water service pipes. Where building sewers must cross water pipes,
the pipe length should be centered over or under the water pipe so
that the pipe joints are as far as possible from the water pipe. If
any joint is less than 10 feet from the water pipe, it must be encased
in concrete. No building sewer shall be laid parallel to or within
three feet of any bearing wall which might thereby be weakened. Whenever
possible, the building sewer shall be brought to the building at an
elevation below the basement floor. The building sewer shall be laid
with a minimum depth of cover of four feet. The building sewer shall
be laid at a uniform grade and in straight alignment where possible.
Changes in direction shall be made with fittings that have offsets
of 60° or less unless a cleanout is installed and brought to the
surface.
In all buildings in which any building drain is too low to permit
gravity flow to the public sewer, sanitary sewage carried by such
drain shall be lifted by approved artificial means and discharged
to the building sewer.
Ductile iron and PVC pipe shall be installed and backfilled
in accordance with ASTM 2321. Blocking under the pipe is not permitted.
Trenches may not be backfilled until the work has been inspected.
If groundwater is encountered or the excavation contains stormwater,
the water level in the excavation must be lowered to a level below
the invert of the public sewer before removing the lateral plug. Cleanouts
must be provided at the City right-of-way.
All joints and connections shall be gastight and watertight.
Ductile iron pipe shall be installed using mechanical or push-on joints
conforming to ASTM C111. PVC pipe shall be joined with push-on joints
or solvent welded joints conforming to ASTM D3034.
All excavations for building sewer installation shall be adequately
guarded with barricades and lights so as to protect the public from
hazard. Streets, sidewalks, parkways and other public property disturbed
in the course of the work shall be restored in a manner satisfactory
to the City.