what does "water greedy" mean in this context?
In a scientific context about recycling waste water:

Is your toilet a low-volume toilet that sends 1.6 gallons or less out of your house with each flush? Or is it an older, water-greedy toilet?

I understand it as "or does it waste more water?" am I right?

Question

what does "water greedy" mean in this context?
In a scientific context about recycling waste water:

Is your toilet a low-volume toilet that sends 1.6 gallons or less out of your house with each flush? Or is it an older, water-greedy toilet?

I understand it as "or does it waste more water?" am I right?

Answer

Yes, you understand it correctly. If it's water-greedy, it uses more water.

Answer

Better:  "Or is it an older toilet, which uses much more water?"

If you say, "Or is it an older toilet, that wastes more water?", that implies that even the low-volume toilet wastes some water, and the "water-greedy toilet" merely wastes more.