On August 19, 1991, the cellar of a two story Brooklyn, New York building became filled with water. As a result of the inflow of water the plaintiff incurred a loss of equipment due to the water damage and blamed a contractor who was working on the adjacent roadway for the basement flooding.

Observation and Analysis

Following were the writer’s observations, analysis and engineering opinion as they apply to this case:

The inspection of a small section of water pipe revealed the following:
a) The pipe measurements were approximately  2″ long; outside diameter 4-1/2″; inside diameter 3-1/2″; wall thickness approximately 1/2″.
b) The pipe appeared to be cut jagged on one side and evenly on the other side. The pipe showed no sign of fracture in bending, nor did it show any sign of fracture in shear. The pipe was cut approximately 7/8th around in a jagged mode and then snapped and removed from the excavation.

The inspection of the exterior of the exterior of the two story building revealed that the approximate area of the cellar was  25′ by 75′, or an area of 1,875 sq. ft. It appeared that the cellar was completely under the surface of the ground surrounding the building.

The National Oceanic and Atmospheric Administration (NOAA) data regarding high and low water shows the following:

The above table shows the heights of the tide in New York Harbor at Battery Park Station above mean sea level (MSL).The National Oceanic and Atmospheric Administration (NOAA) Local Climatological Data shows the hourly rainfall from August 19, 1991 through August 21, 1991 as follows:

There was a total of 2.6″ of rain on August 19, 1991 and a total of 2.8″ of rain on August 20, 1991. The Amount of rain on August 20, 1991 fell in a shorter period of time and probably accounted for greater flooding than on August 19, 1991.Refer to the United States Geological Survey (USGS) water table altitude map for Kings and Queens County, New York for March, 1997. The Water Table Contour Map shows that the approximate water table level in the fourth Avenue area was approximately 5′ above sea level.Refer to the Engineer’s inspection report which states that there was a water stain on the basement wall of approximately 2′ above the basement slab. There was water staining down from the ladder and hatchway that led from the sidewalk. There were heavy earth stains where the sprinkler pipe entered the building. It was not determined the order of occurrence of when the stains developed. There was also no mention in the report of residual water on the cellar floor. This was an indication that the water drained out in the same manner that it entered the cellar. The inspection took place approximately 23 or 24 days after the flooding.

Refer to the deposition of the Plaintiff which stated;

Q. Did you have any other conversation with the workmen beyond what you told me?
A. Yes.
Q. What other conversations took place?
A. They came to me and they told me that a [water] pipe was broken for the sprinkler.
Q. Did you take that to mean a sprinkler your building?
A. No.
Q. Did you take that to mean a pipe that fed the sprinkler of your building? A. Yes.
Q. Did you observe any flooding or seeping of water inside the premises at that time?
A. No.

This portion of the deposition indicated that there was no flooding when the sprinkler pipe to the building was broken the first time in April 1991.

Refer to the deposition of the Plaintiff which stated;

Q. When I asked you how high the water was, you made a gesture with your hands. Is that roughly about three feet?
A. I said between four and five feet.
Q. Between four and five feet. Are there any items that were in the basement that were not damaged by the water?
A. No.
Q. How did the water leave the basement? Did it drain out, was it pumped out?
A. It drained out.
Q. How long did it take for it to drain out?
A. I don’t remember.

In this portion of the deposition the Plaintiff stated that the water drained out of the cellar. The water was not pumped out. This is an important fact. Because if the water drained out, then the water entered the cellar either from under the cellar slab as a result of a rising water table because of the large amount of rain that fell in a short period of time. The other probable and more likely source of water seepage into the cellar was from a back up of the storm/sanitary sewer system. Brooklyn has a combination storm/sanitary sewer system. The sewer trap is located somewhere within the cellar slab below the grade of the slab. The large amount of rainfall overloaded the combined sewer/drainage system and caused a back up in the house line of the building. The level of back up was the watermark 2′ above the cellar slab. In all probability, the water entered through a combination of the three sources. Rising water table, combined sewer back up and through the sidewalk vault doors, however, most of the water entering the cellar was from the sewer/drainage system back up.

Refer to the deposition of General Contractor’s Project Manager which stated;

Q. Do you recall what the nature of the work that was required at this location?
A. Yes.
Q. What was that, sir?
A. We were replacing an existing section of the sanitary and storm sewer.

The General Contractor was replacing a combined storm/sanitary sewer. The combined sewer carried both sanitary sewerage and storm water runoff. Building sewer connections are from the building to the combined sewer. If the sewers were backed up, that is, the volume of water exceeds the capacity of the pipes, then the hydrostatic water pressure that builds up causes the water in the pipes to back up into the house/building connections.

The volume of water in the cellar at a level of two feet (2′) above the slab and for an area of 1,875 square feet is approximately 28,000 gallons. This volume represented the maximum amount of water collected over a one to two day period. If the 3-1/2″ sprinkler pipe was broken and flowing into the cellar at various volumes the cellar would fill to the two foot (2′) level in the following times for a water pressure of approximately 80 psi and neglecting losses:

Referring to the above table one can see that the cellar would fill in approximately one hour if the 3-1/2″ pipe were flowing at maximum opening or breakage. If, on the other hand, the pipe was cracked and flowed at 1 psi, the cellar would fill in approximately 10 hours. However, if the sprinkler pipe were the source of the flow, the water would not stop at the 2′ level unless the sprinkler pipe was one foot above the floor slab for a one psi flow. In all probability, if the sprinkler broke, water from the sprinkler pipe would have filled the entire cellar and overflowed onto the street. This did not occur.