I bought a water softner from Home Depot and their approved installer was Delta Mechanical. What a debacle I had with Delta Mechanical!
They installed the water softner and didn't connect a water seal correctly between the softner and our home's pipe, according to a 2nd plumber from Delta whom came to inspect. A few days the seal failed and our garage was flooded. If we hadn't been at home the water would have entered the house and flooded it completely.
We had to deal (e.g., lots of time) with other companies (Dry Force who were very good) to dry the walls, base board, carpet on steps, etc. Everthing was replaced, repainted and it was a major pain in the AXX! Then Delta wouldn't replace the water softner until I called GE and they comfirmed that the electronics was also fried.
What a MAJOR hassle! Stay away from Delta Mechanical/Home Depot's recommendation unless you want your house flooded.