In fact, pandas can't last long, right?

Every working panda drinks 1 L of water and then produces 3 points in the next 1 hour.

Is this at the beginning? It's hired, it drinks 1 L, it produces 3 points (litres?), so it has a net revenue of 2 per hour, but does it produce 3 more points in the next hour? I imagine that if it consumes 1 litre and produces 3 litres per hour, it's basically producing 2 litres per hour.