When a new house sewer is installed in NYC there are 6 basic types of house sewer connections. All 6 types must meet NYC DEP code requirements. The most commonly used connection is the spur connection. It is likewise the least costly to connect to when it is available.
However, as time has passed it is more and more usual for building lots to be split. This creates new buildable lots and decreases the availability of spur connections. Another factor involving the availability of a spur connection is when previously undeveloped land is developed.
Due to the above factors, other types of house sewer connections have to be utilized and built more often than in the past. If you are developing a property in NYC it is important to familiarize yourself with these connections, as they can add substantial cost to a project.
Your Guide to Home Sewer Connections and The 6 Variations
Even if you are a homeowner this knowledge can come in handy. That is especially true when you require sewer work. What follows is a description of the 6 types of house sewer connections used to connect a property’s sewer to a public or city main sewer line.
1. Spur connection
A spur connection is the most common of all connections used for a house sewer. A spur on a city sewer is a wye in the city sewer with a plug on the outlet side. The plug is removed when a future house sewer connection is made. The spur itself is typically 6″, with the exception being 8″ sizes in Manhattan. This is because the minimum size for a house sewer in Manhattan is 8″.
Having a spur available for connection prevents the need for drilling into the public sewer. A “drill in” or other connection type is more costly. Importantly, if not done properly, can cause damage to the public sewer. In most cases, spurs are ideal as a connection for a home sewer line.
2. Fold in sewer connections
A fold-in connection is required when the city sewer is only one size larger than the connection size required and no spur exists. A licensed sewer contractor would have to fold in a new spur in most cases. This typically occurs when the public sewer is 8″ (which a size no longer legal as a public sewer in NYC) and a 6″ connection is required. This is regardless of if the connection is for a sanitary sewer, a storm, or a combined sewer.
A fold-in requires removing sections of the city sewer. Then folding in three new sections of pipe, one of which is a wye. The wye is to be used as the connection for the house sewer. All new pipe sections must then be encased with an approved concrete mixture. A new fold-in connection adds to the cost of a new sewer installation.
3. Curb connection
A curb connection is usually found on two occasions. A curb connection avoids the need to open the roadway to complete a house sewer installation. The first case is when a new public sewer is installed. Frequently as part of the new public sewer project, a new pipe is installed up to the curb line for each building. A curb connection is also typically placed for buildable lots that have not yet been developed as of yet.
The second case where curb connections are found is when a previous building has been demolished. The service for that property is typically plugged at the curb line, as is required by code. When a property is redeveloped a plugged curb connection can be frequently re-used. A curb connection being available creates substantial savings for the property owner.
4. Drill in sewer connections
When a new connection is required into an NYC sewer and no connection is available, the most usual connection required is a drill-in. This is performed using a core drill machine. It is not permitted to chop into a NYC sewer using hand or power tools.
A hole is carefully cored through the NYC sewer a specific size larger than the pipe size to be connected. In most cases, the city sewer must be prepared before the core drill is done by encasing the public sewer in concrete.
In other cases, a concrete cradle must be installed under the public sewer. The concrete reinforces and strengthens the city sewer from the added stress of the core drilling and the future house connection.
A drill in connection does not add substantially to the cost of a new house sewer. Drill-in sewer connections are made routinely for new house connections throughout New York City.
5. Riser connection
A riser connection is a vertical connection built on the top of a city sewer for use as a connection for a house sewer. Depending on the size and type of the public sewer different designs are used in the construction of a riser. When a sewer riser connection must be built it is a multi-step and fairly costly process.
When is a riser connection required?
It is usual for a riser connection to be required when the depth of the public sewer is greater than 13′. A riser connection can also be required if a groundwater or a rock condition exists. In these cases, it is meant to alleviate the cost to property owners of having to excavate to great depths, or through groundwater and rock, to connect properly to the main sewer line.
If a future sewer repair is needed, a riser also lowers the cost at that time as well. A riser is also required when the difference in elevation from the point where the house drain exits the building to the city sewer is greater than the pitch that is allowed to be used. As sewers work on the principle of gravity, pitching the pipe is used so the wastewater runs off properly.
Only a maximum of 1′ of pitch is permitted for every 4′ of run of pipe. Therefore a riser must be built sometimes when the elevation difference is too great to use allowable pitch. Risers must always be one size greater than the size of the connection size from the building. In NYC where the minimum size of a sewer connection is 6″ the size of a typical riser is 8″. To learn more, read about riser connections for house sewers.
Who inspects house sewer riser connections in NYC?
When a riser must be built, they are carefully inspected by DEP field personnel. A new riser must conform to accepted DEP design standards. All risers must be encased with an approved ready-mix concrete, and also reinforced with re-bar, to provide a long-lasting connection. Interestingly, after the installation is signed off by the DEP the future maintenance and ownership of it reverts to the NYC DEP.
All riser installations are built with a clean-out on the top. This provides a way to clean out any possible future stoppages. If a riser has to be built it will add at least a few thousand dollars to the cost of an installation. Other than having to build a new manhole it is the most expensive connection to build.
6. New manhole connection
In rare instances, a new NYC DEP-approved manhole has to be built for connection to the city sewer. This is required typically for very large house sewer connections such as for a 12″ house sewer.
A manhole connection involves purchasing precast concrete rings from an approved vendor. The other components are a top slab with a ring and manhole cover. Using precast concrete lowers the total cost by eliminating formwork, and the associated lumber and labor. All the steps involved in building a manhole are very closely monitored and inspected by NYC DEP field inspectors.
In terms of cost, the manhole material alone costs well over $2,000.00 including delivery. Other costs, such as labor, ready mix concrete, and roadway restoration, factor into a manhole connection. These costs make it by far the costliest means to connect to a city sewer. In some cases, it is less expensive to install two smaller-sized house sewers to avoid having to build a new manhole connection.
How can this information help you?
New house sewer connections can be a substantial part of the cost of a project. Being familiar with the different types of connections can be very useful when you require this type of work. Knowing the cost factors of each connection type can help keep costs down on your project.
With over 80 years of combined experience, Paul R. Balkan and David Balkan possess extensive knowledge about NYC water main and sewer work. If you have a question or need additional information they welcome your inquiry. All inquiries are responded to promptly.
