Nicky McCullin & Gavin Davidson. SMD Water & Sewer LLC. We do both residential & commercial, consisting of sewer treatment plants, septic tanks, water lines, track hoe, backhoe, house pads, excavation, city & rural water lines, grease traps, road bores, & trenching. Our expertise is in both New Construction & Repair Service. We give free estimates & we are licensed & insured.