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Sanitary and storm pipes start to deteriorate as soon as they're put in place. The cost of rehabilitation often falls on the homeowner's shoulders. Photo: C&K Industrial Services

Sanitary service lateral: the service connection or pipe that connects the building's private sewers to the public sanitary sewer main. This lateral is a straight run of pipe with a depth at the home that depends on whether there is an existing basement. All internal plumbing facilities are connected to this pipe and are individually trapped to prevent odors from entering the home. This pipe is generally vented to the roof of the house, which provides ventilation for the sanitary sewer system.

Stormwater service laterals: the service connections or pipes that connect the building's private stormwater drainage system to the public stormwater system. These pipes are generally 4 to 6 inches in diameter and convey all stormwater that is discharged from roofs, yards, window well drains, and occasionally the groundwater from foundation drains. The typical depth below ground level is 2 to 3 feet and the point of entry to the public storm sewer varies.

There are two basic types of stormwater laterals. One intercepts stormwater downspouts and drains and discharges below ground to a stormwater sewer. The second type of stormwater lateral, referred to as a curb outlet stormwater lateral, discharges to a ditch or to the street through a curb cutout.

Implementing The Program

Drainage areas experiencing I/I should be ranked based on data derived from the installation and maintenance of flow monitors. These monitors should be installed in the downstream sanitary sewer manholes of areas that appear to have excessive wet weather flows. In many cases, these areas may be identified by the amount of basement flooding reported.

Flow monitors should be checked at least once a week, especially before a rain. After one or more rain events, flow data should be reviewed to allow prioritizing of the worst areas for intensive fieldwork. Before any private property testing begins, first perform a manhole inspection, test all public sewer mainlines using a smoke testing, and then dyed water testing. Once the public sewers have been thoroughly tested for mainline problems, the intense testing of private property drainage can begin.

Smoke testing: This is a technique of I/I source detection that is used to locate improper connections or leaks in mainline sewers and on private property. Smoke testing can determine if a problem exists, although it cannot be used to isolate or quantify leaks.

In many parts of Pennsylvania, for instance, plumbing on private property is not conducive to smoke testing because of the piping configuration. Since there is a trap between the home and the mainline sewer that is filled with water, smoke can't pass and potential deficiencies in the piping between the trap and the home are difficult to identify.