Has anyone DD'd or invested in/acquired a sewer construction co?

I have a thesis that corresponds to sewer construction companies and am pursuing a firm that predominately does repair jobs, not new construction. Most of the business is bid through the municipality, some at state level, and a little private. I am familiar with the bid process, cash cycle, and variable project timelines. While the business model is recurring, I wonder if others have found red flags in this sub-market that I am not considering. Hiring a GM to manage bids and project planning would be step one so that I don't invest in a job vs. business. I am happy to have a more detailed conversation on my insights and concerns.