In City of Oroville v. Superior Court, 446 P.3d 304 (Cal. 2019), the Supreme Court of California considered whether the City of Oroville (City) was liable to a dental practice for inverse condemnation damages associated with a sewer backup. The court held that in order to establish inverse condemnation against a public entity, a property owner must show that an inherent risk in the public improvement was a substantial cause of the damage. Since the dental practice did not have a code-required backwater valve — which would have prevented or minimized this loss — the court found that the city was not liable because the sewage system was not a substantial cause of the loss. This case establishes that a claim for inverse condemnation requires a showing of a substantial causal connection between the public improvement and the property damage. It also suggests that comparative negligence can be a defense to inverse condemnation claims.
In December 2009, a dental practice, WGS Dental Complex (WGS), located in the City, incurred significant water damage as a result of untreated sewage from the City’s sewer main backing up into WGS’ building. WGS submitted a claim to its insurance carrier, The Dentists Insurance Company (TDIC) and, in addition, sued the City for its uninsured losses, alleging inverse condemnation and nuisance. TDIC joined the litigation, alleging negligence, nuisance, trespass and inverse condemnation. Under California law, when a government entity fails to recognize that an action or circumstance essentially amounts to a taking for public use, a property owner can pursue an inverse condemnation action for compensation. The City filed a cross-complaint against WGS for failing to install a code-required backwater valve on their lateral sewer line, which would have prevented or minimized the backup.
The City filed a motion for summary judgment, which the trial court denied. WGS then sought a judicial determination on the issue of inverse condemnation. The City presented evidence that the sewage system was designed in accordance with industry standards, and that WGS failed to comply with the City’s plumbing code by failing to install a backwater valve on its private sewer lateral. The trial court found the City liable for inverse condemnation because the blockage that caused the backup originated in the City’s sewer line. The court held that the blockage was an inherent risk of sewer operation. The Court of Appeals affirmed the decision, holding that the City would have had to prove that the WGS’s lack of a backwater valve was the sole cause of the loss in order to absolve itself of liability.