Injury Caused by Public Improvement Liability
"Article I, section 19 (formerly art. I, 14) of the California Constitution requires that just compensation be paid when private property is taken or damaged for public use. Therefore, a public entity may be liable in an inverse condemnation action for any physical injury to real property proximately caused by a public improvement as deliberately designed and constructed, whether or not that injury was foreseeable . . . ." (Chatman v. Alameda County Flood Control etc. Dist. (1986) 183 Cal. App. 3d 424, 431 [228 Cal. Rptr. 257], quoting Souza v. Silver Development Co. (1985) 164 Cal. App. 3d 165, 170 [210 Cal. Rptr. 146].)
"A storm drainage system constructed and maintained by a public entity is such a public improvement. [Citations.] An action in inverse condemnation will lie when damage to private property is proximately caused by use of a storm drainage system for its intended purpose.
The fact that a part of the system may have been actually constructed by a private person will not insulate a public entity from liability, if the system has been accepted or otherwise approved by the public entity. " (Souza v. Silver Development, supra, 164 Cal. App. 3d at p. 170; accord, Chatman v. Alameda County Flood Control etc. Dist., supra, 183 Cal. App. 3d at pp. 431-432.)