Rooftop Water Tanks Proper Maintenance is Essential

Rooftop Water Tanks

New Yorkers love to brag about having the best-tasting drinking water in the country, although

residents of high-rise buildings may not realize that their water makes an extra stop on its way from the reservoir. When high-rise residents turn on their taps to have a drink of water, take a shower or wash the dishes, the water comes from a tank located on the roof of the building. In addition to serving as a storage device, the tank creates water pressure through gravity which brings water to each apartment as needed.

Like other building components and systems, water tanks have to be routinely maintained so they can continue to operate safely and efficiently. A decision to put off maintenance today will most certainly be regretted tomorrow, says Anita Sapirman, president of Saparn Realty, Inc., a Manhattan-based residential property management firm. When it comes to water tanks, preventive maintenance is the name of the game. The water tank requires regular attention to prevent the need for emergency interventions which can be enormously expensive.

Richard Silver, president of American Pipe and Tank Lining Company, a Manhattan-based firm that specializes in water tank maintenance, adds, The cleaning of water tanks is not just prudent maintenance, but New York City law. Tanks containing potable waterthat is, water for consumption purposesmust be cleaned and disinfected no less than once a year. According to New York City Department of Buildings spokesperson Ted Birkhahn, the Building Code sets forth specific guidelines for cleaning the tank as well as for maintaining the physical structure including supports and covers.

Giant Pails of Water

Water tanks haven't changed very much during the past hundred years or so. True, some of the techniques used in their construction have been improved resulting in a shorter manufacturing and installation time, but the overall principle of water tanks remains unchanged. For all practical purposes, water tanks are simply gigantic pails of water, resembling the classic California hot tub covered with a cone-shaped hat, that sit perched on the rooftops of buildings.

According to Wallace Rosenwach, chairman of the Long Island City-based Rosenwach Group, which has been in the water tank business for more than a century, about 99 percent of New York City's residential water tanks are constructed out of woodeither cedar or California redwood. The remaining one percent are constructed out of steel; however, most of the steel tanks that have reached the end of their useful lives are being replaced with wood tanks. Wood tanks are cheaper, they don't corrode and they don't give water a metallic taste. Plus, wood tanks do a better job of minimizing the effects of seasonal temperature fluctuations.

David Hochauser, president of Manhattan-based Isseks Brothers, a water tank manufacturing, installation and maintenance company that has been in business for generations, agrees with this assessment. He says, Wood water tanks are an effective means of delivering clean and sanitary water to a building. And the water tastes good. However, the tank will not do its job, and it will not last, if it is not maintained. An exposed wood tank should last about 20 to 25 years, but it will last even longer if it was well-constructed, if it was properly installed, and, most important of all, if it undergo ffb es routine maintenance. Hochauser points out that, with proper care, the life expectancy of a wood tank can be increased by as much as 30 percent.

Cleaning is a Necessity

An average size domestic water tank stands about ten or 12 feet high, and is as many feet in diameter. The water used for drinking and bathing does not come from the bottom of the tank; rather, it is siphoned off the top. The water in the bottom half of the tank is reserved for fire-fighting purposes and is tapped by turning on the fire hoses found in the stairwells of buildings. The necessity for cleaning the tank stems from the fact that water entering the tank from the City's water source contains some foreign matter, which, over time, settles to the bottom of the tank.

It is not unusual for a tank to accumulate anywhere from a quarter inch to an inch of muddy sediment, a residue that can pose certain health risks, especially to the elderly and to those suffering from deficiencies in their immune systems. According to Hochauser, while these health risks are a matter of concern and should not be taken lightly, they are not in the same category as the respiratory condition known as Legionnaire's disease, which is associated not with water tanks, but with cooling towers that work in conjunction with an absorption unit to provide central air conditioning.

A Thorough Process

The cleaning of a water tank can be completed in a relatively short period of time, and with little inconvenience to building residents, says Gene Andrews, president of Andrews Building Corp., a property management firm in Manhattan. The board president of a 356-unit co-op on the Upper East Side echoed this sentiment when he noted that the work on his building's water tank went so smoothly that he could not state with certainty when the work began and how long it took to complete.

The cleaning process begins by draining the tank so workersusually a two-man crewcan climb inside and scrub the walls and floor with a chlorine solution. The tank is then refilled and a second chlorine solution is added. After the tank has been allowed to soak, it is flushed out. Then the switches are lubricated and any holes are caulked; but, more importantly, the hoops holding the tank's vertical slats in place are tightened. The goal is to make the hoops tight, but not too tight. Hochauser stresses that it is this gentle fine-tuning that translates into longer tank life. The tank is then refilled with thousands of gallons of water and a final check is made to ensure that there are no small leaks. The entire process, which is usually done during a weekday when most building residents are at work, takes about six hours. The cost? Anywhere from $500 to $750.

Not to be overlooked is the maintenance of the tank's supporting structure, says Tom Pasquazi, managing director of Orsid Realty, a Manhattan property management firm. In a worst case scenario a perfectly good water tank may have to be taken out of commission, which means dismantling it and putting the building on bypass, so a deteriorating supporting structure can be replaced. Of course, such extreme measures can easily be avoided if the management company and the building superintendent ensure that the supporting structure is scraped and painted on a regular basis. Pasquazi also notes that some buildings have decorative enclosures to hide their water tanks and to protect them from the elements, which also need to be maintained.

Residential buildings that were formerly commercial buildings may have a second water tank known as a sprinkler tank, used solely to supply water to the building's fire suppressant system. Sprinkler tanks are not continually being replenished with water, as are domestic tanks. Thus, a leak in a sprinkler tank could result in the loss of enough water to jeopardize the building's ability to help extinguish a fire. Even a small leak could create a major problem. The wood, no longer engorged by water, would dry out and separate, a problem that could not be remedied by tightening hoops or ffb by caulking. The only solution would be to replace the tank with a new one, which would cost in the neighborhood of $20,000.

Proper Precautions Pay

In the overwhelming majority of luxury properties we manage, the board members are very intelligent, knowledgeable and dedicated to policies and strategies for prevention, says Sapirman. However, occasionally we are called upon to assume the management responsibilities for a property that has previously operated on what we refer to as a M-wait and see'reactive rather than proactivestance. One such building had a severely compromised, leaking wood water tank. The top of the tank had open areas and was blanketed with pigeons. They were obviously getting at the water. In this case, the tank, which had apparently been neglected for years before we assumed management, was unable to be safely restored and had to be replaced.

Sapirman's first concern was restoring the quality of the water to protect the health of the residents. The building had not been cited but was most certainly in violation of Building Department codes that require the roofing and wood to be maintained in order to prevent the entry of contaminants. After the new tank was installed, the board adopted Sapirman's recommendations concerning regular inspection and maintenance to aggressively prevent the development of another disaster. Sapirman adds, Buildings also need to know about the availability of filtration systems that can be installed to reduce the bacterial content and other impurities that may be impacting the quality or color of the water.

Board members will extend the life of their building's water tank and save money in the long run if they ensure that the tank is routinely and properly maintained. But more importantly, by adhering to prescribed maintenance procedures, board members can rest assured that they are taking the proper steps to protect the health and welfare of the residents of their buildings.

Mr. Johnson is a freelance writer based in Manhattan.

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  • who regulates the quality of the water in the water tank?
  • I live on the 1rst.floor of a 14th floor build.On occasions when i run the faucet on the tub full force I see a tiny featherin the water.Should I say anything to my boss?
  • reverse osmosis filters on Monday, June 7, 2010 12:51 PM
    who regulates the quality of the water in the water tank?
  • Water tanks have changed greatly in the past hundred years. Older tanks may have been made of steel or wood which causes rotting and erosion. Newer water tanks are primarily made out of polyethylene/ plastic. It lasts longer and requires less maintenance. Source:
  • I have a rooftop apartment and the water tank is leaking heavily. Is the building supposed to repair this immediately? I have asked for over 6 months, and have yet to see it repaired.
  • How often to rooftop steel watertanks need chloronation?
  • Kindly advise on how I can insulate my plastic rooftop water tank from the excessive heat & dust in Lahore, Pakistan. Many Thanks
  • I have a grown floor house and water tank is place on Its roof and I have two bathrooms and one kitchen connected with tank but i regularly to face a problem of coming air in my line. So how to rectify this problem permanently. Please guide me about it..
  • How much height do you need to create enough pressure for showering etc?
  • After reading through this entire document; the original question of keeping the tank from freezing was never responded to. Is this the way people do things now?
  • The motor of the roof top water pump (I'm assuming that's it's the motor). A very lound humming sound goes off approximately every 6 minutes for 1 minute. Could that become a hugh problem to the building? And other than the landlord is there anyone else I can complain to?