What is the test for a plaintiff to determine whether a public agency is liable for damages caused by a water main failure?

private damage in each case. (Id. at p. 368, 27 Cal.Rptr.2d 613, 867 P.2d 724.) The reasonableness of the public agency's conduct must be determined on the facts of each case, taking into consideration the public benefit and the private damages in each instance. (Id. at p. 367, 27 Cal.Rptr.2d 613, 867 P.2d 724.) The departure from a strict liability standard was based on public policy: [B]ecause strict liability would discourage construction of needed public improvements which affect surface water drainage, liability exists only if the agency acts unreasonably, with reasonableness determined by balancing the public benefit and private damage in each case. (Id. at p. 368, 27 Cal.Rptr.2d 613, 867 P.2d 724, see also Bunch v. Coachella Valley Water Dist. (1997) 15 Cal.4th 432, 436 [63 Cal.Rptr.2d 89, 935 P.2d 796].)