P trap

There are lots of snow birds where we are staying and just about everyone leaves their gray valve open. It's easy to loose track of time when you're retired.

Many have clothes washers, besides nobody wants to discover their gray tank is full while taking a shower. To prevent sewer smells from going out roof vents we keep a short droop or sag in the middle of our sewer hose run which acts as a trap.

You would think that would create a problem when draining the black tank, but I've never had a problem nor have I seen anyone else clog up their hose.

Bjesquivel wrote:
Does anyone put a makeshift P trap in your sewer hose to prevent sewer smells from traveling back up into your tanks/rv?

Welcome to the forum.

Now enjoy repeated answering of your question, with the same response. I might as well add mine....

As others have said: "WHY" :h

The drain pipes in your house don't have "P" traps in them. Each sink, toilet, shower, drain, etc... all have their own traps. The entire system is vented.

Your RV is a mini-house.

The only time you should get a smell from a closed system is when you connect/disconnect from the campground (CG) sewer system. If you can figure out how to eliminate that....you'll be a billionaire by months end :B

Bjesquivel,

We stay for several months at the Chula Vista RV resort near you. The entire time we are there the sewer hose is connect to our 5th wheel and to the resort sewer connection. I leave the grey tank valve open because we have a washer and dryer. I keep the black and galley valve closed until I dump about every 2 weeks. We never get sewer smells inside the RV.

Close the valves unless you are in the act of draining tanks.

You certainly don't want to leave the black tank open all the time. It needs to get 2/3 to 3/4 full before you dump to create enough flow to force the poo out. You will end up with piles of dry poo if you leave it open all the time. Search for "poo* pyramid". Lots of reading.

Letting the grey tank fill before dumping gives you water to flush out the hose after the black tank is emptied.

Bjesquivel wrote:
Does anyone put a makeshift P trap in your sewer hose to prevent sewer smells from traveling back up into your tanks/rv?

Welcome to the forum. I see this is your first post. As you now know, you do not need a P Trap in the hose. The tanks are vented so, any odors will go out the vent.

And, you should keep at least the black tank valve closed until it's just about full. The tanks dump better when they're full or close to full.
Dump the black tank first, use the grey tank to flush the line after dumping the black tank.

It was not a dumb question, if you don't know, just ask.

Enjoy your travels.

You should have no need for "P" traps in the sewer hose.

Leave your black and grey dump valves closed until your tanks are at least 1/2 to 3/4 full. Then dump the tanks and reclose the valves until the next time.

If you leave your dump valves open all the time, you will eventually get a buildup in your black tank which is going to be difficult to clean out.

There should be no reason to do such a thing.

Both valves should be closed unless you are dumping,hence no fumes to back up.

Your tanks should be vented to the outside via the roof, so smells should not enter into your RV. If they do enter from the tanks, you have either a trap or an air admittance valve that's not working properly in the RV. If there are odors escaping from around the sewer connections (probably between the hose and the campground sewer), then a trap in the hose, makeshift or otherwise, isn't going to help anything.

I try to get my sewer hose as consistently level as possible so that stuff doesn't collect in it. I'm also not usually hooked up to a sewer for longer than it takes to dump the tanks, as I (thus far) have not stayed at a place with full hookups for an extended period of time.

Bjesquivel wrote:
Does anyone put a makeshift P trap in your sewer hose to prevent sewer smells from traveling back up into your tanks/rv?

Never heard of it so I have to ask - why would you want to "protect" the tanks from sewer smells when the contents of the tank smell anyway? :h