We were contracted to install a patio with some addtional small garden walls and plantings. Part of the job included addressing a drainage problem coming from one small part of the property. We addressed the drainage problem by installing a drainage system... Well, we recently had flash flood warnings and torrential downpours and this customers house is situated such that all of his neighbors' runoff comes into his yard. When we first looked at the job and discussed things, the customer only mentioned the section of the property that we corrected...he NEVER mentioned any other parts of the property flooding. So after the flooding rains, he called us and told us the patio was under water from his neighbors runoff coming in. We looked it over and could see that the neighbor needs to install a drainage system or else the problem will continue. This customer feels we are responsible and we said we are not responsible for designing the neighborhood and that it wasnt our fault that everyones runoff goes into this guys yard. The area that we did fix per contract, was not flooding and was working out beautifully. But this guy insists that we better fix the rest of his yard too. I say no and would like some opinions.