As potable water is transported after treatment to the user, opportunities exist for unwanted substances to contaminate it. Water supplies must protect the water from contamination in the distribution system by maintaining a minimum pressure of at least 20 psi, providing a chlorine residual, developing and implementing a cross-connection control program, and providing separation from sources of sanitary contamination including sanitary sewers, storm sewers, drains, private sewage disposal systems and sources of hydrocarbons.
This FAQ document has been developed by the Bureau of Water of the Illinois Environmental Protection Agency in order to increase awareness of the water main protection requirements from sewers by answering frequently asked questions. Water mains must be protected from sanitary sewers, storm sewers, combined sewers, house sewer service connections, drains, and septic fields according to the requirements stated in the Agency Rules For Public Water Supplies (formerly Technical Policy Statements); the formal citation is: Title 35, Subtitle F, Chapter II, Parts 651-654). A copy of the applicable sections is printed on pages 4 and 5 of this handout.
Yes, unless local conditions prevent it. The water main must be located at least ten feet horizontally from any existing or proposed drain, storm sewer, sanitary sewer, combined sewer, or sewer service connection, unless local conditions prevent a lateral separation of ten feet.
If it is not possible to obtain ten feet separation the Agency may approve construction in which the water main invert must be 18 inches above the crown of the sewer. In parallel situations where it is not possible to obtain the lateral or vertical separation, then the Agency may approve construction in which the sewer is constructed of water main equivalent pipe and pressure tested to the maximum expected surcharge head before backfilling.
Agency approval is obtained during the construction permit application process. The construction Page 2 documents must clearly show those locations where the required horizontal and vertical separation cannot be provided. On the back of the Schedule B - Water Main Construction form or on an attached sheet indicate the location(s) where the separation requirements are not met, the reason that proper separation cannot be provided, and how the water main will be protected. The construction permit, which lists the approved plans that clearly detail the situation(s) and indicate the alternative protection, serves as the Agency's acceptance of the deviation(s).
The distance between pipes is measured edge to edge.
No, casing pipe can only be used at crossings where the vertical separation requirement is not met.
No, the exception criteria for gravity sewers do not apply to forcemains. A horizontal separation of ten feet must be maintained in all instances.
No, when the water main crosses below a sewer, the sewer must be constructed with water main equivalent pipe or else either pipe must be installed in a casing. The protection must extend on each side of the crossing until the normal distance from the water main to the sewer or drain is at least ten feet. In addition, the water main must be located at least 18 inches below the sewer. This 18 inches is a structural protection to prevent the sewer from settling and breaking the water main.
If the invert of the water main is not 18 inches above the crown of the sewer when the pipes cross, a casing pipe can be installed around either the water main or sewer in lieu of constructing the sewer with water main equivalent pipe. The casing pipe must be a material that is approved for use as water main. Concrete is not an acceptable encasement. The casing must extend on each side of the crossing until the normal distance from the water main to the sewer or drain is at least ten feet. For example, 30 feet of casing would be required for a 6-inch water main crossing an 8-inch sewer at a 45 degree angle.
In parallel situations where local conditions prevent a ten foot separation the answer is no. At crossings, the answer is yes. Storm sewer constructed with reinforced concrete pipe is not an Page 3 approvable alternative when the storm sewer is parallel to a water main. At crossings when the invert of the water main is not 18 inches above the crown of the storm sewer, the storm sewer can be constructed with reinforced concrete pipe using flexible gaskets instead of providing a casing pipe or constructing the storm sewer with water main equivalent pipe.
No, the water main and sewer must be installed in separate casing pipes, at least ten feet apart, to meet the sanitary protection requirements.
No, the water main should be located as far as possible from manholes. The water main must not pass through or come into contact with a manhole.
Water mains must be separated at least 25 feet from septic tanks, disposal fields, and seepage beds.
Water mains must be separated at least 25 feet from a sewage lift station.
Yes; locate water service taps on a water main so that either the ten foot horizontal separation or 18 inch vertical separation above sanitary sewers, storm sewers, combined sewers, drains, and sewer service connections is provided. For additional information on protection of water service lines refer to the Illinois Plumbing Code or contact the Illinois Department of Public Health.
Yes; the water main protection requirements still apply, regardless of the technique used to install the water main.
The water main protection requirements still apply. Take necessary action to provide the protection options as described in the Agency rules at part 653.119. (See below) Protective measures as detailed in the ‘Standard Specifications for Water and Sewer Main Construction in Illinois' are also generally acceptable. Contact the Permit Section for approval of changes.
For further information, please contact the IEPA, Division of Public Water Supplies, Permit Section.
Water mains and water service lines shall be protected from sanitary sewers, storm sewers, combined sewers, house sewer service connections and drains as follows:
There shall be at least a 10 foot horizontal separation between water mains and sanitary sewer force mains. There shall be an 18 inch vertical separation at crossings. (Agency note: The water main is to be located above the force main at the crossing.)