I have a great opportunity to bid on a commercial building roof here in town. It's 47,000 sqft and about as nasty as roofs get around here, but I haven't done one of this type of roof yet, so reaching out to all of you who have.

I'm not concerned with how to clean the roof itself, although any thoughts or tips would be great. The greater concern is how to capture the run-off and how to charge accordingly for the extra work involved with reclaiming or diverting the run-off.

You can see in the pictures that there are drains coming out of the sides of the building. There are 2-3 of these outlets on each side of the building. They run into the parking lot and then down into the street and eventually a storm drain.

Thanks for any help!