08-27-2003 Regular Meeting and Public Hearing of the La Porte Planning and Zoning Commission

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.. ,:....,~:\ .I . 11. G. Line Size 1. - 2. ) . ,.j' H. ' Line Depth . . 12. Sanitary sewers within the City of La Porte's jurisdiction shall be designed and installed at such a size and depth as to allow for orderly expansion of the system, so as to avoid duplication in the future, and shall confonn with the Comprehensive Waste Water and Sewer Plan for the City of La Porte (as amended where applicable). Sewers shall be separated from water lines by a mininium of 10 feet from outside wall to 'outside wall. For sewers crossing utilities other'than water, a minimum of 6 mches of clearance must be maintained from outside wall to outside wall. 3. The minimum pipe diameter for a public sewer shall be 8 inches. Seryice leads 4 inches -in diameter shall be confined to the limits of the lot which they serve and shall serve only the equivalent of one single-family lot. No' 4- inch sewer shall be l~id in any street, alley, or right-of-way. " Service leads 6 inches in diameter shall not !!erve more than the equivalent of 2 single family lots or other equivalent types of small land tracts: Service leads for single family residential lots shall have a minimum grade of 0.70%. Wastewater flows shall be based, on the current, approved utility phaSing plan for the area. The average day flow for the design of sanitary . sewers shall be based on a minimum of 350 gallons per day ser single family connection for residential areas.' , For cOm.qlercial service leads such as street bores, the required size of the line shall be es~ablished from ,the plumbing drawings. Commercial, industrial, and office areas ,shall be designed for an' avefclge day flow that can be anticipated from the contributing area. Commercial sewer service lead shall be 6'inch pipe or larger and shall not serve more than one commercial connection. Main and lateral 'sewers shall end in manholes. ' The City shall have final review and approval authority as to the size and depths requ~d for sanitary sewers and laterals. 4. 5. 6. 7. 8. 1. The sewer should be laid with the top of the pipe a minimum of 4 feet below the surface of the natural ground or finisbed grade. . . 2. Sewers laid iri street rights-of-way with a curb and gutter section shall have a minimum cover of 4 feet' from the top of the pipe to top of the cur~. The Professional Engineer s~all account for. any anticipated future sewer extension whereas the future sewer extension shall have a minimum 4 feet of cover from the top'ofthe pipe to the top of the curb andthe Professional Engineer of record ' shall adjust the depth of the proposed pipe accordingly. 3. Sewers laid in street rights-of-way with crowned roads and side ditches shall, , have a minimum cover of 4 feet below the flowline elevation of the ditch to the top of the pipe. ' 4. Where the minimum cover as specified in this chapter. is not engineeringly possible, the sewer shall be laid with Class 150 (150psi) pressure pipe with cement stabilized sand backfill in accordance with the Standard Details. Ductile iron pipe may be used but shall be lined with either a polyethylene or polYurethane coating with manufacturer reco~endation and applied by the pipe manufacturer; The minimum liner thickness shall be 40 mil. 5. Maximum depth for 8~li i.qch diameter collection lines shall be 20 feet from average ground 'surface to pipe invert. Depths greater than 20 feet shall require the use of Class 150 (15opsi) pressure pipe with cement stabilized sand backfill in accordance with the ~tand~d Details. Ductile iron pipe .may be used but shall Sanitary Sewer Design Criteria Page 6 of 10