Waterlogged: Complying with the Annual Drinking Water Storage Tank Requirements

Annual inspection results are due Jan. 15.

Rooftop water tanks help deliver drinking water to millions of New York City residents. Based on an inventory of buildings that stand seven stories or taller, it’s estimated that there are 12,000 to 17,000 water towers in New York City. As needed, pumps push water to rooftop tanks where the water is stored until used. When a faucet is turned on within the building, water exits the tank and gravity carries the water to the floors below to be used.

City officials boast that the city’s water system, which originates in upstate New York, provides the finest tap water of any city. But the safeguards in place ensuring the quality of the city’s tap water end at a building’s curb. At that point, it’s the owner’s responsibility to ensure that the building’s drinking water tanks are cleaned, inspected, and tested for bacteria annually, as required by the city’s building and health codes. Poorly maintained water tanks present a potential health hazard for residents.

Among these concerns is the risk of proliferation of harmful bacteria, including E. coli and other waterborne pathogens. Wooden tanks are more susceptible than metal ones to infiltration from animals. Also, biofilms often grow on the inside of the tanks, allowing these harmful bacteria to multiply more easily. Rooftop towers are also susceptible to windblown debris, weather, and sunlight.

We’ll go over the annual maintenance and inspection requirements of drinking water tanks imposed to help combat these health risks.

Annual Requirements

New York City has a set of laws in place requiring owners of buildings that use tanks to store or pressurize the building’s drinking water to inspect and clean them at least once per year. The requirement applies to any tank used to store a building’s drinking water. If the building has a dual-purpose water storage tank that includes a fire suppression system and a drinking water supply system, the tank must be inspected because some of the water is used as drinking water.

Water tanks that aren’t covered by the NYC Department of Health and Mental Hygiene's (DOH) inspection and reporting requirement are ones that are separate from the drinking water supply system, such as a standalone fire suppression tank. Domestic hot water heating tanks are also not subject to this requirement.

Owners must ensure that the water tank inspector submits the results of those inspections to the DOH by Jan. 15 of the next calendar year. We’ll go over these requirements in detail.

Annual inspection. Annual inspections must be conducted for all drinking water tanks that are used to store or pressurize a building’s drinking water [NYC Health Code Article 141, §141.07; NYC Administration Code 17, §17-194]. According to the laws, a physical inspection of each drinking water tank includes the following:

• Assessing the condition of the internal and external tank structures, pipes, access ladders, roof, access hatches, and screen;
• Assessing the presence of pitting, scaling, blistering or chalking, rusting, corrosion and leakage, sediment, biological growth, floatable debris or insects, and rodent/bird activity in or around the tank; and
• Taking a bacteriological (coliform) sample and sending it to a New York State Environmental Laboratory Approval Program (NYS ELAP)-certified lab. Bacteriological means relating to bacteria.

The inspection results must be made available to the DOH by Jan. 15 of the following year and must be maintained by the building owner for at least five years.

If unsanitary conditions are found during the physical inspection, or if coliform bacteria are found in a building’s drinking water, the storage tank from which the sample was collected may be contaminated and require cleaning and disinfection. Any sample that indicates the presence of coliform bacteria, such as E. coli, must be reported to the DOH within 24 hours. Necessary corrective actions, such as cleaning and disinfection, must be taken immediately. The DOH may be contacted by email at watertanks@health.nyc.gov.

Violations may be issued for failure to complete an annual inspection. Inspection must be conducted by a water tank inspector who is either a licensed master plumber or works under the direct and continuing supervision of a licensed master plumber, or is a registered design professional as defined in NYC Administrative Code §28-101.5.

Annual cleaning and disinfection. While the NYC Health Code §141.09 requires that drinking water storage tanks be cleaned if there’s a positive bacteriological result that’s attributed to the sanitary conditions of the tank, the NYC Plumbing Code Chapter 6, §606.5.4.5.3 requires all water tanks to be cleaned at least once a year. These cleanings must be completed only by a person or business with a valid permit issued by the Commissioner of Health and Mental Hygiene.

When a tank is cleaned, the water supply connections to and from the tank must be disconnected or effectively plugged. Then the tank is drained and cleaned. Before the tank can be put back in service it must be disinfected by washing the underside of the top, the bottom, and the walls with hypochlorite solution. The tank must then be filled with water and the chlorinated water must remain in the tank for two hours. After two hours, the tank must be drained completely before refilling for regular use.

Chlorine levels must be taken to validate that the disinfectant levels are below EPA National Primary Drinking Water Regulations. Additionally, a post-cleaning coliform sample should be taken to validate the effectiveness of the disinfection and cleaning process.

A record of the disinfection and cleaning should be kept by the owner for a least five years and made available to DOH within five business days.

Drinking Water Tank Inspectors

In April 2019, the New York City Council passed Intro. No. 1157-B, which for the first time in the NYC Administrative Code and the Health Code defines a water tank inspector as the following:

• A licensed master plumber;
• A person who works under the direct and continuing supervision of such a licensed master plumber; or
• A licensed professional engineer or architect design professional.

As a result of this legislation, as of 2020, only a qualified water tank inspector is allowed to submit a drinking water tank inspection report to the DOH. Prior to this legislation, the law was silent on who was required to conduct such inspections, which were commonly done by building owners or staff themselves.

Intro. No. 1157-B also establishes more stringent criteria for those cleaning, coating, and painting water tanks. The legislation requires that the person conducting maintenance on water tanks is either a water tank inspector or a person who holds a commercial pesticide applicator certification in category 7G issued by the NYS Department of Environmental Conservation or works under the direct supervision of a person holding such certification.

Submitting Reports

The water tank inspector must submit the report on the DOH’s online Drinking Water Tank Inspection Reporting system. To complete the form, the water tank inspector will need to register with a valid email address. After registration, partially completed reports can be saved and finished later. Multiple tanks at a single building must be included in the same inspection report submission.

If you own more than one building, you must ensure that a separate reporting form is submitted by the water tank inspector for each building with a unique Department of Buildings-issued BIN that uses a tank to store drinking water. For example, if a property owner owns three separate buildings, each with a unique BIN and each with a drinking water tank, the water tank inspector would need to file three separate reports.

Make Results Available to Residents

Owners must make residents aware of their rights to review inspection results by posting notification signs in the building with contact information. We’ve provided a Model Notice: Post Notice that Drinking Water Storage Tank Inspection Results Are Available that you can use to post contact information in an easily accessible location within your building. Remember that owners must keep inspection results and water quality test results for at least five years.