There’s no connection to the inside of the house. We just easily drain what we need at the bottoms of the barrels. I’m now working on converting a computer power supply to run a fairly powerful 12 volt water pump (it pulls 9 amps), so we won’t just be dependent on gravity feed. But there’s no reason to connect it to the house’s water system. If we went through a long drought period, I’d just pull the garden hose over to fill it if/as needed. Generally, we get plenty of rain water so even that’s not anticipated.
GS
"Ye hear of wars in far countries, and you say that there will soon be great wars in far countries, but ye know not the hearts of men in your own land."