Go Back   iRV2 Forums > TRAVEL TRAILER, 5th WHEEL & TRUCK CAMPER FORUMS > 5th Wheel Discussion
Click Here to Login
Join iRV2 Today

Mission Statement: Supporting thoughtful exchange of knowledge, values and experience among RV enthusiasts.
  This discussion is proudly sponsored by:
Please support our sponsors and let them know you heard about their products on iRV2
Thread Tools Search this Thread Display Modes
Old 08-19-2016, 10:08 PM   #1
U038340's Avatar
Join Date: Apr 2015
Location: Sunny So. Cal
Posts: 30
Black Tank draining issue "help"

To all you smart RVer's - I have a problem and need some of your awesome advice.

Problem - I drain the Black tank in my 5th wheel after camping and return home to park the RV. I go out camping a few weeks later - pull off the cap and black water (or it appears to be) comes out of the drain line. It's not a spoon full or a cup full, it's more like a bucket full. The valve is closed ofcourse and I can't figure out how this happens. I ensure the tank is fully drained and the black tank valve closed before opening the grey water valve. Help me out folks.

Thanks in advance


2014 Ram 2500
2013 Brookstone 35'
U038340 is offline   Reply With Quote
Join the #1 RV Forum Today - It's Totally Free!

iRV2.com RV Community - Are you about to start a new improvement on your RV or need some help with some maintenance? Do you need advice on what products to buy? Or maybe you can give others some advice? No matter where you fit in you'll find that iRV2 is a great community to join. Best of all it's totally FREE!

You are currently viewing our boards as a guest so you have limited access to our community. Please take the time to register and you will gain a lot of great new features including; the ability to participate in discussions, network with other RV owners, see fewer ads, upload photographs, create an RV blog, send private messages and so much, much more!

Old 08-19-2016, 10:35 PM   #2
Senior Member
jfran304's Avatar
Tiffin Owners Club
Workhorse Chassis Owner
Join Date: Oct 2009
Location: Warner Robins, GA
Posts: 2,555
Unless you can tilt your trailer so the black tank drain will be low you won't be able to get everything out. It sounds like your black tank drain valve is leaking and you can either replace it or try to clean it. Some paper may have gotten stuck in it and lets it leak. You can get one of these to insure that when you take the cap off nothing will come out.

Twist On Waste Valve, 3 - $18.65

My black tank valve was getting hard to operate so I bought one just in case. You may be able to find one cheaper, I just used this one for an example.


Jon & Sue Francis (Retired U.S.A.F.)
Lil Girl-Rescued, Abby Rescued, Peaches Rescued
06 Allegro 35TSA Workhorse Chassis
2013 Chevy Spark Dinghy
jfran304 is offline   Reply With Quote
Old 08-19-2016, 11:42 PM   #3
Senior Member
MtnTrek's Avatar
Join Date: Jul 2015
Location: Currently; SW Cali. Sunny & warm!
Posts: 1,134
Welcome to the forum,
Sorry to hear that.
X2 ^^^ my thoughts as well. It's difficult to know where the drain line exits the holding tanks. Are you sure no one ran anything down any drains in that length of time? Don't forget to empty the bowl before travel too.
We use the "valve" as well while parked, but we don't travel with it on.
I'd perhaps use one of these if this has happened a second time.
Walmart usually has them.

Be well.
DRV Suites ES-38RSSA #9679
J & J
GM Denali, 3500HD-Max, 4x CC, 8' DRW,
MtnTrek is offline   Reply With Quote
Old 08-20-2016, 06:17 AM   #4
Senior Member
Join Date: Jul 2015
Location: Fairbury, Nebraska
Posts: 118
Is it possible that the 3" sewer line runs a little uphill from the tank to the cap? I have seen dump stations where the road slopes away from the drain. If either of these occur, you could have stuff left in the low spot of your pipe that then runs out the next time you open the cap. Other than that, there could be small "stuff" in the edges of your valve that don't let it fully close, how does it feel when you close it? Another thing I do when dumping is that I leave the black valve open when dumping grey so a little bit washes back and helps clean out that black pipe. Depending on your parking situation, can you run some fresh water into the black tank after dumping that will 'slosh' around as you drive, then find a place to dump it when you get home or close to home?
Tightwadted is offline   Reply With Quote
Old 08-20-2016, 03:55 PM   #5
Senior Member
Join Date: May 2001
Location: Spicewood, Tx
Posts: 636
I agree the black valve is probably leaking, the tank isn't fully empty, and motion on the return trip is further emptying the tank. Check it as soon as you get home with the valve closed, then open it. In total you will probably get that bucket full.
dayle1 is offline   Reply With Quote
Old 08-20-2016, 07:44 PM   #6
Senior Member
egwilly's Avatar
Outdoors RV Owners Club
Join Date: Jul 2012
Location: So Calif
Posts: 673
Yep, been there, done that.....it's leaking at the seal. Easy to replace once you thoroughly drain and flush it.
2016 Outdoors RV Glacier Peak 26RLS
2014 Ford F350 Superduty 6.7 Diesel.
egwilly is offline   Reply With Quote
Old 08-21-2016, 12:02 AM   #7
Senior Member
Join Date: Jun 2016
Location: Nine Mile Falls WA / Arizona City AZ
Posts: 648
Sometimes its hard to verify that the black water tank valve closes and seals... I've had issues with mine.... so I installed another valve where the outlet cap is located... so that when I pull the cap, there is not a bucket of stuff that rolls out....

I also use a clear plastic elbow on my hose so that when I dump/flush the tanks I know that when the water runs clear its safe to close the valves...

We always try to than fill the toilet 3 times and add a cup of either washing machine soap or oxy-clean.... its our thought that as we drive down the road... the water will mix with the soap and wash the inside of the tank...
Retired Business Owner, Re-manufacturing HD Clutches, Brake Shoes, Air Compressors, Sales & Installation of PacBrake and other Industrial Friction
jelag is offline   Reply With Quote
Old 08-21-2016, 09:47 AM   #8
Senior Member
Gigattime's Avatar
Join Date: Mar 2016
Posts: 971
Agree that there is either something in the valve that is preventing it from sealing completely or the black valve us leaking. It is not really the best idea (IMHO/research - others may have their own opinion) to leave the black tanks empty/dry. Once I dump the blank tank, flush/rinse, and close the valve, I always set it up for the next outing/trip with Camp Kem and at least a gallon of water. This prevents future smells and helps digest anything that didn't come out and might still be in the tank. 17 years and no blank tank issues. Good luck on an easy repair should your valve be leaking...happy camping!
Gigattime is offline   Reply With Quote
Old 08-21-2016, 09:54 AM   #9
Senior Member
Join Date: Aug 2001
Location: FL
Posts: 1,339
It's either a bad valve or something wedged in the valve body preventing it from fully closing. Either way, the valve will have to be pulled out for replacement or repair.
--2005 F350 Superduty Crewcab, 6.0, 4wd, short bed, 3.73 gears
--2016 Montana 3711FL, 40'
--SOLD 2014 Wildcat 327CK, 38'
ralphie is offline   Reply With Quote
Old 08-22-2016, 07:43 PM   #10
U038340's Avatar
Join Date: Apr 2015
Location: Sunny So. Cal
Posts: 30
Thank You all very much. I ended up ordering the twist on valve that was recommended and as a interim fix. I'll have the valve fixed upon return from vacation because based on your advice I believe the valve is leaking. I towed the 5th wheel last weekend and just to verify the leak I got a bucket and twisted off the cap and it had black water that came out (valve closed). Also, I learned from you all to add water and possibly some tank treatment after draining the black tank, so thanks for that lesson, I didn't know that I was supposed to do that. Thanks again everyone.....I always get quick replies that help.

2014 Ram 2500
2013 Brookstone 35'
U038340 is offline   Reply With Quote
Old 08-24-2016, 09:19 AM   #11
Registered User
Join Date: Jul 2015
Posts: 168
Not sure if you do this or not, but try opening and closing the valve numerous times while dumping. It may dislodge whatever is in your valve. You can also backflush your tank with an adapter on the outlet and do the same thing...opening and closing the valve. Either way will also "slosh" the contents of the tank, moving some of the more solid material around.
donnandon is offline   Reply With Quote
Old 08-27-2016, 09:55 PM   #12
Join Date: Jun 2016
Location: Prairie Grove, AR
Posts: 39
Mike, I think you made a wise choice in getting a twist on valve. I have one that I keep on my 5th wheel at all times but, for the same and different reasons. If I'm at a dump station that I cannot hook up my tank wash, I will close it after I empty my black tank, but keep the black tank valve open then open one of my grey tanks and back flush into black tank for about I don't know 15-30 seconds I'm guessing, I just turn it off before my small grey tank is empty. I shut off grey valve open twist on valve and drain black water again. The main reason I have it is so when I'm dry camping I can equalize my 2 grey tanks and have 82 gallons of grey water capacity for kitchen and bath. But I have had I'm thinking toilet paper stick in the black valve and not seal all the way, this way I don't get a surprise when I take the cap off. Just my 2 cents worth.

Retired Professional Firefighter
2007 Nuwa Hitchhiker DA329RSB
Teek312 is offline   Reply With Quote

black tank, tank

Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off

Similar Threads
Thread Thread Starter Forum Replies Last Post
Black tank not draining cmcguire48 Travel Trailer Discussion 18 05-28-2016 08:28 AM
Bathroom Sink draining to Black Water tank bassoneman Class A Motorhome Discussions 18 04-10-2015 06:05 PM
Any suggestions on black tank draining issues?! NewbieToThis iRV2.com General Discussion 27 03-04-2015 11:30 AM
help with draining black tank Mulcahy iRV2.com General Discussion 12 07-21-2013 05:31 PM
BLACK TANK: "can we" or "can we not" leave the black tank open in an RV park?? doodlebug52 Travel Trailer Discussion 15 12-02-2009 09:56 PM

» Featured Campgrounds

Reviews provided by

Copyright 2002- Social Knowledge, LLC All Rights Reserved.

All times are GMT -6. The time now is 02:54 AM.

Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2018, vBulletin Solutions, Inc.