@LukeAlmighty @MaleGoddess @Terry @LukeAlmighty Yes
“The design is such that water from the supply line channels through the faucet for you to wash your hands. And then drained out through the sink drain and into the tank. The water will keep flowing to fill up the tank, until it gets shut off by the float,” wrote the review site. “This way water is not wasted. Compare to the usual when you have to wash your hands on a separate sink with clean water [which amounts to] more water used for each visit to the toilet.”
https://www.snopes.com/fact-check/sink-toilet-japan/
Is it fresh water, from the faucet?