Specifications include, but are not limited to: A. Horizontal Separation: 1. Sewers, including manholes, should be separated at least 10 feet, horizontally, from any existing or proposed water mains. Should local conditions prevent a lateral separation of 10 feet, a sewer may be closer than 10 feet to a water main if: a. it is laid in a separate trench; or if b. it is laid in the same trench, with the water main located at one side of a bench of undisturbed earth; and if c. the elevation of the top (crown) of the sewer is at least 18 inches below the bottom of the bottom (invert) of the water main. B. Vertical Separation: 1. Whenever sewers cross under water mains, the top of the sewer shall be at least 18 inches below the bottom of the water main. 2. When the elevation of the sewer cannot be varied to provide the required 18" vertical separation, relocate the water main, for a distance of 10 feet extending on each side of the sewer, with one full length of water main centered over the sewer so that both joints will be as far from the sewer as possible. 3. Water main should be constructed of AWWA slip-on or mechanical-joint ductile-iron pipe. Sewers shall be constructed of AWWA mechanical-joint ductile-iron pipe for any portion within 10 feet of the water main with the sewer joints equidistant and as far as possible from the water main joints. Both sewer and water main services shall be pressure tested to assure watertightness prior to backfilling. Where a water main crosses under a sewer, provide adequate structural support for the sewer to prevent damage to the water main. C. Special Conditions: Where it is impossible to obtain proper horizontal and vertical separation as specified, construct the pipelines as specified above and, in addition, encase the sewer line with minimum 6" cement concrete for 10 feet on either side of the water main. D. If utilities involved do not cover the cost of the above items and the Contractor is charged by the utilities or the Contractor does the work, the cost will be handled by Change Order.