Is it normal to fill up the grey water tank this fast?

My wife lets the water run rinsing vegetables, cleaning dishes, brushing teeth and showering. I ask her not to do it, she does it anyhow. She can fill a 62 gallon grey tank in 2 days. Pretty much relegates us to full service sites only. Oh well, we've found plenty we like. By the way, the grey tank never festers because it is being flushed so often.