Your doing the right thing, they are just selling product .
If they install a drainage system, they do not need to install one for each home.
The roofs should be draining into gutters that go away from the building, not down into a drainage system that is being installed that close, if they overflow from debrie, they fail.
IF a water problem starts....Get a reputable site person out there, the ones you have now are questionable.
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