As the majority of the work is completed outside, we have quite a bit of flexibility in this regard. We do ask that someone is present for the interior installation of the backflow-preventer to the main water line. This typically takes about 2 hours. While we generally install controllers outside, if you would like for it to be installed inside such as in the garage, we would ask for access to that area throughout the day as well. Otherwise, no one is required to be present until we are complete.