I grew up in a house that had a well that ran dry in the summer. This prepared me for RV'ing to the point where I usually need to use more water in the black tank to make it dump smoothly.
We typically get 2-3 showers, a bath for our 2 year old, and a dish washing or two out of a 30 gallon grey tank, and 5 days or more out of our 30 gallon black tank. I have a tote that I can either tow to the dump station or leave in the back of the tow vehicle and pump to. I use a little harbor freight 12V hose pump 12 Volt Marine Utility Water Pump
and a garden hose to pump the grey water in and out of the tank. It's pretty convenient.
At home conserve water fairly well but do a huge amount of laundry. Our 2 year old has decided that if she likes a food she will rub it all over her body and hair. I really hope she grows out of that soon... she loves food.