A lot depends on what they were dumping.... Laws and rules vary from place to place, including campground to campground (rules) within the same city but
Black Water MUST be dumped in a proper sewer system, Don't matter where you are that one is universal
Gray water (Sinks, including the kitchen sink, Showers and washing machines) In some areas may be dumped on the ground.. But in many areas needs to go with the black water.
WASH water: Wash water is the same as gray water only NO food particles, so NO kitchen sink allowed Some RV's have 3 tanks (Mine for example) and one of them is WASH water.
Wash water can often (But not always) be dumped legally.
Also, there is sometimes a distinction between "FRESH" dish water and "Stored" dishwater.
Many PUPs have no toilet, the only drain is the kitchen sink, No shower, NO toilet (Or a cassett or porta-pottie) and in this case what they were dumping was fresh kitchen sink water.
