What the Archimedes' Principle and Empty In-Ground Swimming Pools Have to Do With Insurance Coverage

HOMEOWNERS – PROPERTY – IN-GROUND SWIMMING POOL – PRESSURE OR WEIGHT OF WATER EXCLUSION – EFFICIENT CAUSE OF LOSS
Gravino v. Allstate Ins. Co.
(4th Dept., decided 5/7/2010)

The street streaking, "Eureka!" shrieking Archimedes of Syracuse (Greece, not New York) reportedly discovered the principle of bouyancy while taking a bath and trying to figure out a way to determine whether King Hiero II's goldsmith had made the king's new laurel wreath crown from solid gold or had dishonestly added silver to it:

Any object, wholly or partially immersed in a fluid, is buoyed up by a force equal to the weight of the fluid displaced by the object.

Hydrostatic pressure is the pressure exerted by a fluid at equilibrium due to the force of gravity.

When an in-ground swimming pool is full of water, it exerts a force downwards due to gravity (weight) that is greater than that of the hydrostatic pressure, if there is any, that is exerted upwards on it by the water table.  When that pool is emptied, however, the force exerted downwards by the pool is less.  If the water table is lower than the bottom of the pool, no hydrostatic pressure exists and the pool does not move.  If the water table is higher than the bottom of the pool and the point at which the empty pool's weight equals the water table's hydrostatic pressure, however, the empty pool becomes buoyant and the pool "pops". 

That's what must have happened to the Gravinos' in-ground swimming pool, and they made a claim to their homeowners insurer, Allstate, for the damage to the pool's concrete that occurred when one end of the pool lifted out of the ground.  Plaintiff had drained his pool in June to paint it, but the painting was delayed due to rain.  Five days later, the Gravinos witnessed Archimedes' principle in action.  Allstate denied coverage for the damage based on, among other things, a policy provision in the policy excluding damage to a swimming pool caused by "pressure or weight of water."

Plaintiffs sued and the parties moved and cross-moved for summary judgment.  Erie County Supreme Court (Donna M. Siwek, J.) denied Allstate's motion and granted plaintiffs' cross motion.  On Allstate's appeal, the Appellate Division, Fourth Department unanimously REVERSED the order/judgment and vacated Supreme Court's declaration in favor of the plaintiffs, noting that since this was a breach of contract and not a declaratory judgment action, the court should have dismissed plaintiffs' complaint.

Finding that the efficient or dominant cause of the loss of the pool damage was excluded hydrostatic pressure, the Fourth Department held:

Defendant met its initial burden on its motion by establishing as a matter of law that the exclusion for damages caused by "pressure or weight of water" upon which defendant relied unambiguously applied to plaintiff's loss, and plaintiff failed to raise a triable issue of fact in opposition (see generally Zuckerman v City of New York, 49 NY2d 557, 562). The experts for each party agreed that the pool had lifted from the ground because of the hydrostatic pressure in the soil surrounding the pool. The fact that plaintiff's expert stated in his affidavit that the damage would not have occurred if plaintiff had not emptied the pool does not remove the loss from the policy exclusion. The policy expressly provides that, where the damage has two or more causes, the loss is not covered if the "predominant cause(s) of loss is (are) excluded" under the policy. Here, "[t]o determine causation, [we must] look[] to the efficient or dominant cause of the loss', not the event that merely set the stage for that later event' " (Kosich v Metropolitan Prop. & Cas. Ins. Co., 214 AD2d 992, lv denied 86 NY2d 707). Here, although the drainage of the pool may have been a precondition to the lifting of the pool from the ground, we conclude that defendant established as a matter of law that the groundwater pressure was the "predominant cause" of the loss, thus rendering applicable the policy exclusion for damages caused by "pressure or weight of water" (see Jahier v Liberty Mut. Group, 64 AD3d 683, 685).  

This blawg's discussion of the Javier v. Liberty Mut. Group case is here.

Water weighs 8.35 pounds per gallon, so the water in a 20,000-gallon swimming pool would weigh 167,000 pounds or 83.5 tons.  Remove that weight, add five days of rain to the water table beneath a pool, and cry "Eureka!" if it pops.  Just don't expect your homeowners insurer to cover any resulting damage if your policy contains an exclusion identical or similar to the ones in this or the Javier case.