When a residential building is connected to the NYC sewage, there are six basic connection types that meet code requirements. The spur connection is the most common and affordable, but other types may be required based on building and sewage conditions:
- Splitting existing lots to create new ones has become a common practice. However, this means only one of the resulting properties has access to the existing spur connection.
- Building projects in undeveloped land may also lack access to a spur connection.
Knowing the required connection type is very important for property developers in NYC, since it can add considerable project costs. This article provides an overview of the six main types of sewage connections allowed by the NYC Department of Environmental Protection (DEP).
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1) Spur Connection
Spur connections are the most common and affordable, as mentioned above, and their configuration is very simple:
- A spur connection uses a wye fitting that is already installed in the city sewage line, with a plug on the outlet.
- The plug is removed when a new sewage connection is required.
- The minimum diameter for a spur connection is 6”.
- Manhattan is the exception, since the minimum diameter allowed is 8″.
When a spur is available, the connection cost is reduced drastically because there is no need to drill into the public sewage. Spurs are ideal for new sewage connections, but availability is the main concern. All other options involve additional work, and their cost is higher as a result.
2) Fold-In Sewer Connection
This connection is used when a spur is unavailable and the city sewage is only one size larger than the required connection diameter. In this case, a sewage contractor must fold in a new spur. For example, this applies when a property requires a 6” connection and the sewage line has a diameter of 8”, which is no longer allowed in NYC.
The installation procedure of a fold-in sewer connection can be summarized as follows:
- A section of the city sewage line is removed.
- Three new piping sections are folded in, including a wye for the new sewage connection.
- The new piping sections are encased with an approved concrete mixture.
- Once the wye is in place, the installation procedure is like that of a spur connection.
Even though a fold-in connection has a layout similar to a spur connection, there is an additional cost due to the new piping segments and wye that must be installed and encased in concrete.
3) Curb Connection
During new public sewage projects, a pipe is normally installed up to the curb line of each building and undeveloped lot. The main advantage of a curb connection is not having to disturb the road during excavation.
Curb connections are typically available after new public sewage projects. However, they can also be used if an earlier building was connected to the public sewage at the curb line and according to code. When an existing curb connection in a redeveloped property is considered suitable, the building owner can achieve substantial savings.
4)Drill-In Sewer Connection
When the spur and curb connections previously described are not possible, a drill-in connection is normally used. This connection type can only be performed with a core drill machine, and NYC does not allow hand or power tools for the task. The following procedure is used:
- A hole is drilled in the sewage line, with a specified size larger than the pipe being connected. Drilling must be carried out with great caution.
- The existing sewage line must often be encased in concrete to offer support while drilling. Alternatively, a support may be installed under the public sewage line.
- After the drilling procedure, the concrete reinforcement is left in place to support the new sewage connection.
Preventing damage to the NYC sewage is extremely important during the drilling process, since other properties depend on the sewage line to which the new connection is added.
5) Riser Connection
A riser connection uses a vertical pipe to connect the residential sewage line with the city sewage.
- This connection type is normally used when the public sewage is buried at a depth greater than 13 feet, but there are exceptions.
- A riser connection is useful when other options require an excavation through rock or groundwater, which is more complex and expensive.
- Riser connections are often required when another type of sewage connection would exceed the maximum pitch allowed - 1’ of pitch for every 4’ of pipe.
Risers must always be one size larger than the building sewage connection. Since the minimum connection size in NYC is 6”, the minimum riser size is 8”.
Risers are carefully inspected by the NYC DEP, ensuring they are built according to the accepted design standards. All risers must be enclosed with an approved concrete mix and reinforced with rebar to guarantee a durable and reliable connection. They must also include a clean-out at the top for maintenance purposes such as removing a stoppage.
The riser connection is the second most expensive type after the manhole connection, which is discussed in the following section.
6) Manhole Connection
In rare cases, the NYC Dept. of Environmental Protection requires an approved manhole for connection to the city sewage. This normally applies for very large residential connections such as a 12” pipe. A manhole connection uses many special components that are not required with other connection types:
- Precast concrete rings from an approved vendor.
- A top slab with a ring and manhole cover.
When a manhole connection is used, the cost of materials alone is typically a few thousand dollars, and then you must consider skilled labor and roadway restoration. You can expect rigorous monitoring and inspection from the NYC DEP during the manhole construction process.
Manhole connections are the most expensive. However, they can sometimes be avoided by using two smaller connections of another type, with a lower total cost.