Thank you for your replies.
You know, I did try a search but, the thing with those searches is that you have to know how to ask the question. I usually screw up and end up asking the wrong question. I think I tried something like; 99 damin hornet specifications; I should have tried something simpler.
Thanks again.
My reason for asking is that he only wants to go weekend camping with us at places with full hook-ups because he thinks after he and his wife each take 2 showers and wash dishes his gray holding tank will be full. Looks like if he doesn't be careful with water usage he could be right. Personally , I can go days without problems but, I conserve water and take Navy type showers.