Water left in Black Tank after flushing

[TravelingZoo]

Hi. I have a 2013 27RLSWE Cougar. A couple of days into my last trip, I started getting a strong sewer smell in my RV. The black tank indicator only showed 1/3 full. The smell would come and go so I emptied the black tank without flushing. The next day I started getting the smell again. The next day I was leaving so I emptied the tank and flushed it until the water started running clear. However on the way home, we stopped to eat lunch and the trailer smell of sewer again. After I got home, I partially filled the tank and took it to the local dump station and flushed it three times. I looked down the toilet and was able to see clear water. After getting home the water was brown again and the water was about an inch deep. I have not had any smell since then but the water is still brown. I use the recommended chemical in my tank. Is it normal for there to be water left in the tank after flushing. I let it run until it completely stopped. Any advice on the smell problem and whether it is normal for there to be water left after draining would be appreciated. Sorry for the long post.

[Retiredsorta]

I have a 2011 Bullet 278RLS. Very similar size for comparison. My black tank is 30 gals. I had a black tank flush kit installed when I bought it new. I use it every time I dump. You didn't mention if you have one. I always add 2 gals fresh water and 1 bottle of the Thetford toilet chemical to start off with. I've never experienced the smell I have read from others. You'll get many opinions from some knowledgeable rv'rs. This just seems to work for me. As far as you having water left in tank, not sure how much is left in mine as the tank is offset from toilet. I just know that the "bottom" of my toilet is clear after dumping.

[S&Dfz331]

I used to get that smell in my 5er and I found if you fill it with a few gal of water like the above post said before you hit the RD I found this to work. I also put a little bit of liquid water softener in my tank it will help clean out the tank when you go to dump. And if you dump your tank before you leave your camp site fill with a few gals of water and toilet chem. Then add the liquid water softener so it can slash around while going down the RD. That should help keep you tank clean and odor free.

[therink]

X2 on water. After I dump my tank I then fill tank to about half full using the back flush and then dump again. Sometimes twice. I then rinse until water is clear (can take 10 minutes or so). I then add about 5 gals water with flusher before I hit the road. I never let the tank run dry until winterizing time.
Using this method I never have odors and have never needed to add any chemicals. The key is lots of water. The tanks are very wide and very flat. Any areas of the tank with residue that are not in contact with water will generate odors. And once that stuff dries it is very difficult to remove later.

[Tinbender]

Hey Zoo,
Just a thought on something to check.

Is your tank vented out through the roof or do you have one of those Disney Character vacuum breaker/vents hidden in a cabinet somewhere? If so there could be a problem with the flapper seal and that will give you the sewer odor.
Tinbender

[TravelingZoo]

Thanks everybody for the information. I do have a black tank flush which I use every time that I drain the tank. My tank is vented out the roof. I took the cap off and ran water down the vent pipe to make sure that it wasn't clogged. Thanks again for all the helpful information.

[GaryWT]

Sometimes I put extra chemicals in after the flush with water and at times when we go camping if there is a smell with the first flush of the weekend, we add more. I have only uses the tank wash system once this year.