Getting hard water out of pipes?

When you have your tinaco cleaned, has anyone ever dumped about four or five gallons of vinegar in the bottom and run it through the pipes and let it sit for 24 hours? Then rinsed it through to get the gunk adhering to the inside of the pipes out? It would be the same principle as running vinegar through your coffeemaker.

This house was twenty years old when I bought it and, for the last fifteen years of those twenty, was only rented out for half the year. Water sitting in the pipes and drying out and the hard water getting deposited on the inside.

Or? Throw me some ideas that don't include a water softener please.

LOL! I took out the behemoth hot water tank within a month of moving in and replaced it with an on demand water heater... no tank. So, I'm not worried about that.
I was also thinking of wrapping a coffee filter or cheesecloth around each of the taps (after draining the water out and then turning them off again before adding the vinegar) so I can get an idea of how much crud comes out. Which will give me an idea of whether to do it again immediately. Small house... kitchen taps/bathroom sink taps/shower taps and three outside outlets. Do you think five gallons would do it?

I also think your plan will partially work...the "hard" mineral laced water at your home is coming in from the municipal water being supplied..so the mineral residue will continue unless treated..I am fighting the same issue..Good luck.