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Mine is probably the simplest set up shown so far; but, sometimes, “simple” makes the brain’s “lights” come on:

The water tank is 12 gallons. The clear tube is for air; the white, is for water intake; the clear, reinforced tube is the actual water line.

Water line runs from the bench to the sink cabinet under the bed’s foot support board.

Under-sink connections for the water and drain lines.

Sink top and faucet.