[Amended 9-7-2010 by Ord. No. 24-10]
All roofs, paved areas, yards, courts, courtyards, or areas using a topping or finish capable of collecting water shall be drained into a separate storm sewer system, or a combined sewer system, as per §860-169E, where such systems are available. Alternatively, as a green initiative, structural and nonstructural stormwater management practices separate from a storm sewer or combination sewer may be employed as long as they comply with Document 363-0330-002, Best Management Practices for Storm Water Management, issued by the Pennsylvania Department of Environmental Protection, available electronically at http://elibrary.dep.state.pa.us, or are of a best management practice design that meets or exceeds the requirements of the above-noted document and meet the requirements of the Administrative Authority and the local municipality. If there is no storm or combined sewer available for such drains, or if an individual chooses to construct an alternative system specified above, then the water from said drains shall be conducted by proper pipe or pipes below the surface of the sidewalk, to the street gutter or to a place of disposal satisfactory to the Administrative Authority, where the local municipality has no ordinance or regulation in place, and in accordance with any other plans or ordinances adopted under the Storm Water Management Act, 1978, October 4, P.L. 864, No. 167,[1] or other ordinances or regulations of the municipality involved. In no case shall collected surface water or stormwater be allowed to drain over sidewalks or driveways, or onto adjacent properties where the water can create soil erosion or have adverse effects on a structure.
[1]
Editor's Note: See 32 P.S. § 680.1 et seq.
Storm water shall not be drained into sewers intended for sewage only. Also, where infiltration of storm, ground, or seepage water into the sanitary system exists, corrections to eliminate this condition shall be made and is the responsibility of the owner or his/her agent.
Storm drains, conductors, traps, fittings, etc., shall be of materials as provided for in Article V, "Materials, Standards and Areas of Permitted Use."
A. 
Size of building storm drain. The size of the building storm drain or any of its horizontal branches having a slope of 1/2 inch or less per foot, shall be based upon the maximum projected roof or paved area to be handled according to the following Table 860-164A, "Size of Horizontal Storm Drains."
TABLE 860-164A
Size of Horizontal Storm Drains
Maximum roof and paved areas for drains of various slopes
Dia. of Pipe
(inches)
1/16" fall per ft.
Sq. ft.
1/8" fall per ft.
Sq. ft.
1/4" fall per ft.
Sq. ft.
1/2" fall per ft.
Sq. ft.
*2
N.P.
N.P.
400
580
*2
N.P.
N.P.
750
1,050
3
N.P.
N.P.
1,160
1,644
4
N.P.
1,880
2,650
3,760
5
N.P.
3,340
4,720
6,680
6
N.P.
5,350
7,550
10,700
8
8,200
11,500
16,300
23,000
10
14,800
20,700
29,200
41,400
12
24,000
33,300
47,000
66,600
15
42,000
59,500
84,000
119,000
18
73,000
103,000
145,000
205,000
21
110,000
155,000
220,000
312,000
24
155,000
220,000
310,000
440,000
27
215,000
304,000
430,000
610,000
30
280,000
400,000
565,000
805,000
33
360,000
520,000
730,000
1,000,000
36
460,000
650,000
920,000
1,300,000
42
700,000
990,000
1,390,000
1,900,000
48
990,000
1,400,000
1,990,000
2,800,000
NOTES:
*
Not permitted underground.
N.P.
Not Permitted.
B. 
Size of vertical conductors. Vertical conductors shall be sized on the maximum projected roof area, according to Table 860-164B, "Size of Vertical Conductors."
Table 860-164B
Size of Vertical Conductors
Diameter of Leader Pipe
(inches)
Maximum Roof Area
(square feet)
2
720
2 1/2
1,300
3
2,200
4
4,600
5
8,650
6
13,500
8
29,000
C. 
Size of combined sewers. To compute the size of a combined sewer the method of Subsection A shall be used. The fixture units shall be converted into an equivalent projected roof or paved area. When the total fixture unit load on the combined sewer is 256 fixture units or less, the equivalent drainage area in horizontal projection shall be taken as 1,000 square feet. When the total fixture load exceeds 256 units, each additional fixture unit shall be considered the equivalent of 3.9 square feet of drainage area.
D. 
Values for continuous flow. Where there is a continuous or semi-continuous discharge into the building storm drain or building storm sewer, as from a pump, ejector, air-condition plant, controlled flow roof drainage, or similar device, each gallon per minute of such discharge shall be computed as being equivalent to 24 square feet of roof or paved area.
Building subdrains located below the public sewer level shall discharge into a sump or receiving tank the contents of which shall be automatically lifted and discharged into the drainage system as required for building sumps.
Every sump or receiving tank receiving the discharge of clear water such as rain water, subsoil or seepage drainage, shall be of materials as provided for in Article V, "Materials, Standards and Areas of Permitted Use."
A. 
When subsoil drains are placed under the basement floor or used to encircle the outer walls of a building, they shall be protected by an accessibly located back water valve before connecting to the building storm or combined drainage system. Where connected to separate storm drainage system, and the connection is made on the building side of the main leader trap, no other trap will be required other than the back water valve, where the connection is made on sewer side of main leader trap, they shall be effectively trapped, or they may discharge into a properly trapped area drain or catch basin. Where connected to a combined building drain, they may discharge through a cellar or basement floor drain using a four inch running trap provided with an accessibly located back water valve. These drains shall have a connection of not less than four inches in diameter. The final connection of the collected water with the storm or combination drainage system shall require a plumbing permit and be inspected by the Department. And when such drains are connected with the storm or combination system, such connection shall be performed by a registered master plumber. Where no storm or combined sewer is available, the water shall be drained or pumped to a point of disposal satisfactory to the Administrative Authority where the local municipality has no ordinance or regulations in place.
B. 
Piping used for the collection of subsoil or seepage drainage shall be of approved material as provided for in Article V, § 860-65D. The pipe shall be laid on no less than four inches and covered with no less than six inches of crushed stone or gravel of medium size and arrangements made to cover the pipe with a material to prevent, as much as possible, sand or dirt from washing into and clogging the stone or gravel bed and cover.
A. 
Where required. Conductors and storm drains when connected to a combined sewer or public storm sewer system shall be trapped.
B. 
Where not required. No traps will be required for storm water drains which do not connect to a public storm sewer or combined sewer system.
C. 
Trap material. Storm water traps when required shall be of materials conforming to the type of piping material used, except when underground they shall be of approved material. Traps for area drains or catch basins shall be of approved material.
D. 
Method of installation. Individual storm-water traps shall be installed on the storm-water drain branch serving each conductor, or a single trap shall be installed in the main storm drain at the building wall before its connection with the combined building sewer, or when independently connected to the public storm or combined sewer.
A. 
Where required. All buildings shall be provided with proper conductors for conducting the water from the roofs in such manner as shall protect the walls and foundations of said buildings from injury.
B. 
Not to be used improperly. Conductor pipes shall not be used as soil, waste, or vent pipes nor shall drainage or vent pipes be used as conductors.
C. 
Outside conductors and connections. Outside conductors may be of sheet metal, or other approved material but they must connect to the storm drainage piping by extending the pipe at least one foot above grade level. All outside sheet metal conductors shall be connected to the pipe as direct as possible, in a vertical position and no sheet metal conductor shall be run horizontally across the outside walls of a building.
D. 
Protection of rain water conductors. Rain water conductors installed along alley ways, driveways, or other locations where they may be exposed to damage shall be protected by metal guards, recessed into the wall, or be constructed of galvanized steel pipe to a height which will afford the necessary protection.
E. 
Combining storm with sanitary drainage. The sanitary and storm drainage system of a building shall be entirely separate, except that where a combined sewer is available, the building storm sewer may be connected in the same horizontal plane through a single wye fitting to the sanitary sewer. Such connection shall be made downstream of the sanitary building trap at or beyond the properly line or at a location approved by the Authority.
F. 
Double connections of storm drains. Where the sanitary and storm drains are connected on both sides of the combined sewer, single wye's shall be used and the requirements of Subsection E relative to the location of connections shall also apply.
No portion of the storm drainage system installed underground or below a basement or cellar shall be less than three inches in diameter. Outside underground storm sewers shall be a minimum of four inches in diameter.
A. 
Material of roof drains. Roof drains shall be of materials as provided for in Article V, "Materials, Standards and Areas of Permitted Use."
B. 
Roof drain strainers, general use. All roof areas, except those draining to hanging gutters, shall be equipped with roof drains having strainers extending not less than four inches above the surface of the roof immediately adjacent above roof level, of not less than 1 1/2 times the area of the conductor to which the drain is connected.
C. 
Flat decks. Roof drain strainers for use on sun decks, parking decks, and similar areas, normally serviced and maintained, may be of the flat surface type, level with the deck and shall have an available inlet area not less than two times the area of the conductor to which the drain is connected.
D. 
Roof drain flashings required. The connection between roofs and roof drains which pass through the roof and into the interior of the building shall be made watertight by use of proper flashing material.
Expansion joints or sleeves shall be provided where warranted by temperature variations or physical conditions, such types of joints or connections shall be subject to the approval of the Administrative Authority.
Where separate systems of sanitary drainage and storm drains are installed in the same property, the storm and sanitary building sewers may be laid side by side in the same trench.
In lieu of sizing the storm drainage system from conventional methods as previously described in this Chapter, the roof drainage may be sized on controlled flow and storage of the storm water on the roof provided the following conditions are met:
A. 
The water of a 100-year frequency storm is not stored on the roof for more than 24 hours.
B. 
The water depth on the roof does not exceed three inches during the above storm.
C. 
The roof is dead level and 45-degree cants are installed at any wall or parapet.
D. 
Roof design for control-flow roof drainage shall be based on a minimum of 30 pounds per square foot loading to provide a safety factor above the 15 pounds per square foot represented by the three-inch design depth of water. This factor should definitely be kept in mind as a prime requirement for assuring a structurally sound roof.
E. 
Flashing extends at least 6" above the roof level and scuppers are placed in the parapet wall 3 1/2 inches above the roof level.
F. 
No less than two drains are installed in roof areas 10,000 square feet or less and at least four drains in roof areas over 10,000 square feet.
G. 
Control of runoff from flat roofs shall be by proportional weirs; no valves or mechanical devices shall be permitted.
H. 
Drainage from control flow which is based on gallons per minute of flow shall be converted to equivalent square feet of roof or paved area, on the basis of each gallon per minute of flow being equivalent to 24 square feet of area as provided in § 860-164D, Drains not equipped with weirs, such as area drains, may be connected to the controlled flow system, provided the square feet of area, including the converted gallons per minute flow to square feet are added together and the drain is sized to convey the sum of all loads in accordance with Tables 860-164A, "Size of Horizontal Storm Drains," and Table 860-164B, "Size of Vertical Conductors."