Your home or building may be susceptible to sewage backups if the lowest drain is less than 24" above the nearest upstream manhole. Most building codes require owners to install a backflow prevention valve to minimize the chance of flooding at properties with drains that meet the specification mentioned above.5 L3 y/ |# ]* H. J, S1 C9 c/ B
; z) N- h# U9 j# n. j: o. @' ybackflow prevention valvesHow does it work? A backwater valve can be installed in the basement at the exit point from the home or building, or in the sewer lateral outside of the building. 7 R3 [* D/ n3 ]' b/ z: }! l
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The "lateral" is the underground pipe that carries sewage from private property to the city’s sewer main. The backflow valve is installed downstream and prevents sewage from backing up into the lateral beyond ("above") this valve