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.