This was a new one for me. Maybe others have seen similar in your area?
According to the sellers, the PVC pipe located at the front of the garage was used for softener salt delivery. Multiple homes in this development had it. 2nd picture is of the other end of the pipe capped near the softener as the service is no longer offered.
How much will people pay for salt delivery when you can buy bags for $5.00-$10.00 at Walmart?
At the same time, how low can you charge for that type of service to draw customers and still make money?
Probably why the service is no longer offered. That, and many municipalities have upgraded their treatment systems to the point where softeners are often not needed.