If this is your first visit, be sure to
check out the FAQ by clicking the
link above. You will be required to register
before you can post: click the register link above to proceed. To start viewing messages,
select the forum that you want to visit from the selection below.
There are a few deferent kinds some go to a sewer line,some a septic tank, and some around lakes go in to a holding tank. It sounds like this one runs in to a tank and you were hitting the baffle of the tank. The baffle is where most clogs happen so when you hit that it will open. But is it happens again in a short time, have them get someone out to pump the tank. If it is a commercial RV dump it might have a grinder in line before it hits the sewer but you should see the grinder box close to where the dump is.
Might be a counter to see how meany gallons are dumped. Most places charge by the gallon. When I was pumping septic tanks we had to summit a sample of every load, but they took our word for how meany gallons. the RV dump just used a flat rate.