Our 14-story, 90-unit cooperative on the Upper East Side recently had a condition assessment performed by an engineer to help with future capital planning. They informed us that we need to install backflow preventer devices on our building’s water service lines because it is mandated by the City. I’ve lived in this building for 30 years and have been on the board for 10 years. Why exactly do we need backflow preventers, and why is this the first I’ve heard about this requirement?
An installed backflow preventer (blue device, center) protects the public water supply from contamination.
One billion gallons of clean drinking water are distributed to the taps of nine million New Yorkers each day, and it’s vital to keep this water clean. The city’s water supply system, overseen by the New York City Department of Environmental Protection (DEP), includes approximately 6,800 miles of water main pipes below our city’s streets, and connects to every building in the city. The water that enters buildings from this extensive system is clean and potable, but there exists the potential for contaminated water inside buildings to flow back into the city’s water supply via back pressure or backsiphonage. This is prevented by properly installed backflow prevention devices.
Since 1980, backflow preventers have been legally mandated for certain buildings by the New York Sanitary Code and the Rules of the City of New York. The regulation was not strictly enforced until a push in recent years by the DEP’s Cross-Connection Control Program, an initiative that includes regular random inspections of New York City buildings to make sure they are in compliance.
In addition to hospitals and factory buildings, residential dwellings with large or treated boilers, roof tanks, cooling towers, and multiple water service lines also fall under this requirement, as well as businesses such as restaurants, supermarkets, laundries and dry cleaners, barber shops and beauty salons, medical and dental offices, photo-processing facilities, and art studios where paint and chemicals are used.
What is Backflow?
Backflow is the reverse flow of non-potable water or other substances into the public water system, such as chemically treated water from boilers, cleaning fluids from businesses, foam or toxic antifreeze solutions from fire sprinkler systems, and water from cooling towers with pathogens and bacteria like Legionella, which causes the potentially fatal Legionnaires’ disease. Contamination can occur at any point of connection between a potable water pipe and a source or system containing non-potable water and other unwanted materials, also known as a cross connection.
Backpressure backflow in a building results when the pressure in the system is greater than the pressure of the incoming potable water supply. Backpressure can be caused by pumps or temperature increases in boilers, or if there is a decrease in the water supply pressure. Backsiphonage occurs when negative or reduced pressure develops in the supply piping and forms a vacuum, usually due to an interruption or drain in the supply, such as water main repairs or breaks, or nearby firefighting activity. To prevent backflow, a backflow preventer device is installed on each main water service line—domestic and fire water—feeding the building. A common type of backflow preventer is the reduced pressured zone (RPZ) assembly.
Installation
Backflow preventer installation requires the services of a licensed professional engineer (PE) or licensed registered architect (RA), and licensed master plumber (LMP). A licensed professional can help you determine if your building requires a backflow preventer or multiple devices, or if you qualify for an exemption. Exemptions, which are granted in extremely rare cases where the building is deemed to not pose a risk to the water supply, must be filed with the DEP by a PE or RA on behalf of the property owner. If your building has an existing backflow preventer, but the DEP has no record of its installation, you must have a licensed professional file a record drawing of the device, as well as an initial test report of the device for DEP review.
Responsibility for installation falls upon the owner of the property or the co-op or condo board. Owners and boards of buildings that are issued an order by the DEP to install a backflow preventer must file plans with the DEP within 30 days. If the DEP has not received certification from a PE, RA, or LMP that the backflow preventer is at least in the process of being installed within that time, a Notice of Violation will be sent out. Violators will be liable for a civil penalty of up to $1,000 issued by the Environmental Control Board (ECB). Continued non-compliance can ultimately lead to civil and criminal actions and proceedings, as well as the termination of water service to the building.
If the device is not installed, violators can face a $1,000 fine.
It can take several weeks for backflow preventer installation and compliance to be completed. First, plans for each device to be installed must be drawn up by a RA or PE, and an application for approval sent to the DEP, which may take up to three weeks or more to process and approve. Rejected plans must be revised and resubmitted to the DEP approval queue, which can add another several weeks to the timeline.
Approved plans are then filed with the New York City Department of Buildings (DOB) and a plumbing permit is issued. Installation itself is relatively quick. It typically takes a plumber just a few days to modify the service piping to accommodate the new backflow preventer. Proper planning is needed to minimize disruption to residents and any businesses located in the building. Once installed, a PE or RA must inspect each installed device and a New York State Certified Backflow Prevention Device Tester needs to test the system. When testing is complete, a test report must then be submitted to the DEP within 30 days of installation.
Cost
Backflow preventer installation costs vary based on the specific site conditions, the size and quantity of the water service(s), and the proximity to a floor drain. For each device, the cost can range from a base of $7,500 to $15,000 for midsize buildings and $15,000 to $35,000 for larger buildings; this does not include the PE’s or RA’s design fees. The DEP filing fee is $350 per service connection and the DOB filing fee is a little over 1% of the estimated plumbing cost. The size of the device is also a factor in cost. For example, a one-inch device can start at $225, while a three-inch device could cost $2,800. Labor costs also increase with pipe size.
The addition of a backflow preventer reduces water service pressure to the building; additional, more significant costs can occur if the drop in water pressure becomes an issue for residents. A PE or RA can help determine if installing a pump or larger size water service and backflow prevention device would counteract the pressure loss.
Follow Up
The law also requires annual testing and inspection by a certified tester, and a report submitted to the DEP. Failure to comply can lead to penalties and termination of water service. Because backflow preventer devices are made up of moving parts, seals, and springs and are subject to corrosive substances, wear, and fatigue, it’s critical to properly maintain them to ensure they properly operate and play their part in keeping our city’s drinking water safe.
Stephen Varone, AIA is president and Peter Varsalona, PE is principal of RAND Engineering & Architecture, DPC. This column was originally published in the January 2017 issue of Habitat Magazine.
