Standard Utility Separation

[Will007]

Hi,

Anyone know what the standard utility separations are for sewer, water, storm drain, and secondary water?

Both vertical and horizontal.

Thanks in advance for your help.

 

[WILDWINGS27]

Sewer and Water are ussually 10' hor. and 1.5' vertically

 

[msquared48]

And the sewer line UNDER the water line.

Mike McCann
MMC Engineering

 

[Will007]

What about water and storm drain, and water & irrigation?

 

[WILDWINGS27]

Same rules apply unless you are using a water main quality pipe

 

[civilperson]

Local municipality will have standards that you must follow, (each city different).

 

[bimr]

Each reviewing agency had a regulatory standard on this, but the standard set forth by the various reviewing agencies are more or less the same. However, you should check with the reviewing agency where your project is located to be sure.

Here is an example standard from one reviewing agency:

c) Relation to Water Mains
1) Horizontal and Vertical Separation
A) Whenever possible, a sewer must be at least ten feet horizontally from any existing or proposed water main.
B) Should local conditions exist which would prevent a lateral separation of ten feet, a sewer may be closer than ten feet to a water main provided that the water main invert is at least eighteen inches above the crown of the sewer, and is either in a separate trench or in the same trench on an undisturbed earth shelf located to one side of the sewer.
C) If it is impossible to obtain proper horizontal and vertical separation as described above, both the water main and sewer must be constructed with water main quality pipe and joints that comply with 35 Ill. Adm. Code 653.119 and shall be pressure tested in accordance with "AWWA Standard for Installation of Ductile-Iron
Water Mains and their Appurtenances," ANSI/AWWA C600-93 (1994) (no later editions or amendments) for a working pressure equal to or greater than the maximum possible surcharge head to assure watertightness before backfilling.
2) Water-Sewer Line Crossings
A) Whenever possible, sewers crossing water mains shall be laid with the sewer below the water main with the crown of the sewer a minimum of 18 inches below the invert of the water main. The vertical separation shall be maintained on each side of the crossing until the perpendicular distance from the water main to the sewer is at least 10 feet. The crossing shall be arranged so that the sewer joints will be equidistant and as far as possible from the water main joints. Adequate support shall be provided for the water mains to prevent damage due to settling of the sewer trench. Refer to Appendix H, Drawing No. 1.
B) Where a sewer crosses under a water main and it is not possible to provide an 18-inch vertical separation, the following special construction methods shall be specified (refer to Appendix H, Drawing No. 2): i) The sewer shall either be constructed with water main pipe and joints that comply with 35 Ill. Adm. Code 653.119 and shall be pressure tested in accordance with "AWWA Standard for Installation of Ductile-Iron Water Mains and their Appurtenances," ANSI/AWWA C600-93 (1994) (no later editions or amendments) for a working pressure equal to or greater than the maximum possible surcharge head or shall be encased in a carrier pipe with the ends sealed, that, along with the joints, complies with 35 Ill. Adm. Code 653.119.
ii) The water main quality sewer or carrier pipe shall extend on each side of the crossing to a point where the perpendicular distance from the water main to the sewer is at least 10 feet.
iii) For the required length of the water main quality sewer or carrier pipe, omit the select granular cradle and granular backfill to one foot over the crown of the sewer and use selected excavated material (Class IV) and compact to 95% of Standard Proctor maximum density.
iv) Point loads between the sewer or sewer casing and the water main are prohibited.
v) Adequate support shall be provided for the water main to prevent damage due to settling of the sewer trench.
C) Where it is not possible for a proposed sewer to cross under an existing water main, the specifications shall require the construction methods set out in subsection (c)(2)(B) above and shall require that any select granular backfill above the crown of the water main be removed within the width of the proposed sewer trench and be replaced with select excavated material (Class IV) compacted to 95% of Standard Proctor maximum density. Where a proposed sewer must cross over proposed water main, an 18-inch vertical separation shall be maintained. Refer to Appendix H, Drawing No. 3.
3) Sewer Manhole Separation From Water Main No water pipe shall pass through or come into contact with any part of a sewer manhole.