It is common that a homeowner in the 5 boroughs may suffer from a non-functional sewer due to a lack of sewer line pitch or a back pitched sewer line. The most common reasons for a lack of pitch are:
1. The existing house sewer line pitch was not properly supported upon the initial installation; proper support consists of solid concrete blocks inserted underneath the sewer line as well as proper compaction of the surrounding soil.
2. If a level was not used to properly measure pitch of the pipe. Measuring back pitch with a level should always be performed when installing a sewer; it is very important especially when there is a minimal amount of elevation from the house sewer trap to the point where the pipe connects to the city sewer line AKA spur connection.
3. Shoddy plumbing work is another common factor leading to a back pitched sewer line. It is common for a general contractor to install the sewer line when building a new house however, the proper installation of a sewer line requires a sewer specialist. There is a great deal of experience and attention to detail required in each aspect of the sewer installation, everything from the excavation process to the back-fill and tampering of the soil upon completion.
What are the NYC DEP requirements for pitch on a sewer line?
The NYC DEP code allows for a 1/8” of pitch per a foot of pipe on a 4” and 6”sewer line. When dealing with larger pipes such as 8”, the minimal amount of pitch is 1/4” per a foot of pipe. To many peoples surprise, there is such a thing as too much sewer line pitch. DEP plumbing code allows for 1’ for every 4’ of pipe as the maximum pitch. In the event of too much pitch, the flow rate entering the private sewer may impede with the flow of the public sewer system. A riser connection may be required; this is a type of sewer connection where a vertical pipe is installed perpendicular to the city sewer, to decrease the sewer pipe slope from the house to the city sewer. Another option would be for the house to be lowered which would also decrease the amount of back pitch, ultimately decreasing the difference in elevation levels.
What size pipe does your home require?
Most sewer lines in Brooklyn, Queens and the Bronx consist of 6” pipe, older homes may have had a 4” sewer line installed when the house was originally built, 4” pipe is no longer permitted for a new sewer line replacement or installation. When dealing with very large buildings, it is very common to find an 8” sewer line as it may carry large amounts of disposal that a 6” sewer line may not be able to handle. Most buildings in Manhattan were built with 6” or 8” sewer lines. It is now required that all sewer line installations or replacements in Manhattan must include an 8” pipe, 6” pipes are no longer allowed to be installed.