Keep in mind that if you camp at a forestry or corp of engineer park with no hookups, there may be another facility of theirs within a short distance where you would be allowed to fill with water and dump tanks because you are camping with them. There are many of these type parks that do have dump stations and sometimes their various parks are all around the same body of water. We camped and entire summer with no sewer hookup. The tank can be used for black also - do black first, then grey, then rinse at dump station when done. Ours had a lower gate you just pulled open -- no fuss - no mess and you didn't get it on you.