Seeing Plumbing and HVAC deals marketed as 40% EBITDA margin, is this actually possible?

I've seen a number of HVAC and Plumbing deals recently where the CIMs are reporting 40%+ EBITDA margin. Smaller shops with 8-10 employees and $3-4m of revenue. Owners are still involved in the field, so replacing with a GM will bring the margins down but even then it would still be 35%+. Are these margins actually possible in these fields or does it not pass the sniff test right away?