Sewer smell inside RV....Help needed....

You posted this same topic on Face Book and were given the same answer, close your grey tank valve, as well as your black tank! Problem solved, oh but you might have to go out every couple of days and drain the tanks? Don't try and take short cuts.

Jwireman89 has a great suggestion. I have found that some campground sewer systems siphon the drainwater from traps. I think making a loop drop of sewer hose could help minimize the siphoning. We experience the dreaded sewer odor probably once a year. Closing off grey valve always corrects. Often just running water in all drains eleviates issue. Because this happens randomly and we haven't changed our practices I attribute the occurances to campground drain systems sucking our drains dry.

If you are using a slinky sewer hose, you might try making a trap by letting the hose slump down in a U shape on the way to the hookup.

Do you have a washer/dryer prep in your RV? A lot of times people overlook keeping that trap full if it is unused.

We learned early in our camping experience to keep the valve closed, and open only to empty. Otherwise smells do come up through the sinks. No reason to leave them open anyway, you want both tanks to be filled when emptied so you have a force of water flushing everything out.

one_strange_texan wrote:
I may have this wrong, but if you leave your gray water tank drain valve open, hooked up to the sewer hub and therefore empty, you are inviting the fumes from the park sewer system to back up into your tank & sink drain if you do not have a trap in it, if the trap is not filled with water or if it is working improperly. I leave all drains closed and dump intermittently. Gray water is a good flush of the sewer hose after dumping black water.

If there is a problem with the traps, the OP should still get the fumes from the gray tank when the valve is closed?

I agree, I also keep the black and gray valves closed until they need dumped.
Maybe a different/better air admittance valve will help?
If possible, temporarily rubber band a plastic bag over the air admittance valves and open the gray tank valve. See if it makes a difference. Just because the air valve is new, it doesn't mean it is working properly.
Make sure the traps are filled and holding water before you check the air admittance valves.

one_strange_texan wrote:
I may have this wrong, but if you leave your gray water tank drain valve open, hooked up to the sewer hub and therefore empty, you are inviting the fumes from the park sewer system to back up into your tank & sink drain if you do not have a trap in it, if the trap is not filled with water or if it is working improperly. I leave all drains closed and dump intermittently. Gray water is a good flush of the sewer hose after dumping black water.

In my opinion this is spot-on.

I may have this wrong, but if you leave your gray water tank drain valve open, hooked up to the sewer hub and therefore empty, you are inviting the fumes from the park sewer system to back up into your tank & sink drain if you do not have a trap in it, if the trap is not filled with water or if it is working improperly. I leave all drains closed and dump intermittently. Gray water is a good flush of the sewer hose after dumping black water.