What is the general rule of thumb for towing a travel trailer that has liquid in the holding tanks? I get that the liquid adds weight, but if I camp off the grid and the grey and black water tanks are semi full, is the trailer designed to handle that? Where do I dump it? Do I just go to a campground and ask to use their dumping station? Would there be a cost to just dumping the grey and black water tanks?New to this so appreciate any advice.Thanks,

My general rule is to dump as soon as I can. We had one incident a few years ago where we camped at a lake high in the mountains with no dump sites. Although not totally full, when coming off the mountain we were at an angle where the grey tank backed up into the shower and overflowed onto the floor. As far as dumping, most rv parks will let you dump for a fee. In Oregon many state parks will let you dump for free. Some states still have free dump sites at road side rest areas.

You should be able to tow easily with holding tanks full or nearly full. Actually, the travel motion will facilitate the breaking up of any solids and make the next dump much more efficient. Most campgrounds will allow passing through RVers the use of the dump station for a fee. Many truck stops (Old Flying J's) have a dump station, most charge a small fee. Some road side parks have a dump station but those are rare. Some RV dealers have a dump station also. There are apps for your smartphone that shows dump locations.

I OFTEN wind up traveling with at least SOME of my waste tanks full and sometimes MOST of them full but when the waste tanks are full the FW tank is empty so not that MUCH of an increase in weight. There SHOULD be no issues with towing with full tanks but some smaller trailers design the tanks as ballast so if yours is one of those you COULD notice a difference in handling. Most larger trailers (15 feet and up) don't have this issue.Good luck / Skip

Moved from Forum Technical Support

All trailers should be able to travel with full black and gray water tanks, but some can't. There are some Airstreams that have had frame issues from folks traveling with full tanks. As crazy as that sounds, some trailers just aren't built right. Having said that, I would dump my tanks at the first reasonable opportunity.

towing travel trailer with full holding tanks?

29 Replies

Searching_Ut
Explorer
Jul 04, 2013
Between friends, family, and workmates I know literally hundreds of people with campers, most of which tow with full tanks, and none of which have had any issues with the tanks. A couple have had frame issues, but those are the ones that tried to go ultralight with the aluminum frames and structure members. Even the low end springdale TT I had a couple years ago had enough carrying capacity to where I was almost 500 lbs under my max when loaded for camping to include a full load of water. Again, how are you going to boondock, or camp in backcountry areas if you don't have water? When it's time to leave are you just going to dump your tanks on the ground as a present for the next people? As for filling all the tanks, for my type camping it doesn't work out quite that way. For the most part I just end up transferring from the fresh to the grey and black over the course of the trip. On longer trips I do sometimes take 35 or so extra gallons of water in the back of the truck as my freshwater tank only holds 50 gallons while the greys hold 80. We don't do that often though as we tend to move spots after 4 to 5 days.

The advice to check you tank mounts, along with virtually everything else on your rig on a regular basis is a very good idea. No matter the brand, these things a pretty much just thrown together and you'll find stuff needing tightened, re-routed or repaired. Things also work loose over time, especially if you travel a lot of miles over rough roads.
goducks10
Explorer
Jul 04, 2013
I have no problems towing with full tanks. 5'er has 4315lbs of payload. We're using 1500lb of that for regular camping stuff. That leaves me with 2815lbs for water. At the most we would have 78 gals of grey/black, that equals about 640lbs. Still have 2175lbs left. The reason we bought a Northwood product is for the in house built frames and the high CCC. I'm not proposing that everyone tow with full tanks, but shopping around and looking at weight margins makes a big difference. Too many units out there with 1400-1600lb CCC. Load up your gear and then fill the tanks and starting driving 100+ miles down the road and maybe those are the people that are having the trouble.
Huntindog
Explorer
Jul 04, 2013
Take a deep breath and relax. I never said that anyone should exceed any ratings...Yes there are some TTs built with ridiculously light CC...I said that any trailer that wasn't capable of towing with full tanks, had a design flaw....This would be one of them.

Often we have someone on here say that GVW doesn't matter, only what the TT actually weighs...Of course they are trying to justify towing with a undersized TV...But yes this is a reason that it matters.

As for myself, my TT and TV are very capable. That is a priority for me when trailer shopping.
myredracer wrote:
If anyone says towing with full tanks is no problem, I say that they are playing with fire.

The first thing you should do if you want to do this is go weigh your trailer at a scale and see what the actual wet/loaded weight is and then compare that to your GVWR. Then, and only then, decide if you want to tow your trailer and exceed the GVWR.

Many trailers weigh too close to the GVWR when loaded for camping. If we were to travel with a tank full of fresh water, we would be overloaded. If we were to travel with all 4 tanks full, we'd be more than 1,000 lbs over the GVWR. I am not going to do it. If you really want to and your trailer is still under warranty, I would see if your dealer will give you something in writing that will cover a crack or failure if you tow with one or more full tanks. I doubt they will do it. The first thing Lippert will try and say is that you overloaded your frame and walk away from it.

For those that insist that trailers should be and are built to handle the weight of water, then you would do good to start reading all the posts you can find on the various RV forums out there about owners who have had cracked frames, failed welds and broken tank support straps from overloading their trailers. It happens a lot more than people realize. Frames these days are being built on the thin edge of barely being able to support just the UVW. Frames typically aren't even I-beams anymore, they're 3 pieces of sheet metal welded together to look like an I-beam and they flex like crazy. If you knew what your frame was really like, I doubt that anyone would think it was no problem.
subcamper
Explorer II
Jul 04, 2013
myredracer wrote:
If anyone says towing with full tanks is no problem, I say that they are playing with fire.

The first thing you should do if you want to do this is go weigh your trailer at a scale and see what the actual wet/loaded weight is and then compare that to your GVWR. Then, and only then, decide if you want to tow your trailer and exceed the GVWR.

Many trailers weigh too close to the GVWR when loaded for camping. If we were to travel with a tank full of fresh water, we would be overloaded. If we were to travel with all 4 tanks full, we'd be more than 1,000 lbs over the GVWR. I am not going to do it. If you really want to and your trailer is still under warranty, I would see if your dealer will give you something in writing that will cover a crack or failure if you tow with one or more full tanks. I doubt they will do it. The first thing Lippert will try and say is that you overloaded your frame and walk away from it.

For those that insist that trailers should be and are built to handle the weight of water, then you would do good to start reading all the posts you can find on the various RV forums out there about owners who have had cracked frames, failed welds and broken tank support straps from overloading their trailers. It happens a lot more than people realize. Frames these days are being built on the thin edge of barely being able to support just the UVW. Frames typically aren't even I-beams anymore, they're 3 pieces of sheet metal welded together to look like an I-beam and they flex like crazy. If you knew what your frame was really like, I doubt that anyone would think it was no problem.

x2

I never tow with full tanks, on about 5 gallons in the FW tank if we need to stop on the way and use the bathroom.

When out TT was 2 years old, I had to take the underbelly cover off for a mod I was making (adding macerator pump). I was shocked at the mounting of the grey and black tanks. They had angle iron pieces that run along their length at each side and then a flat piece is welded to the angle iron end so it can bolt to the frame crossmembers. The angle iron supports were fabricated about 3/8" too short so they didn't butt the crossmember. Which means the self-threading screws they used to attach it to the crossmember were no longer in shear (screws would have to break across them to fail)but were in a pull-out mode (all the screws had to do was pull out of the hole) which is far weaker. The angle support had dropped about 3/8" at the end and was in the process of pulling out the screws. If I had travelled with full tanks, it almost certainly would have failed. I repaired them with a spacer and through bolts.

If you really want to travel with full tanks, have a trusted friend or mechanic-type who knows what they are doing inspect the tank mounting to verify everything is ok.

Steve
myredracer
Explorer II
Jul 04, 2013
If anyone says towing with full tanks is no problem, I say that they are playing with fire.

The first thing you should do if you want to do this is go weigh your trailer at a scale and see what the actual wet/loaded weight is and then compare that to your GVWR. Then, and only then, decide if you want to tow your trailer and exceed the GVWR.

Many trailers weigh too close to the GVWR when loaded for camping. If we were to travel with a tank full of fresh water, we would be overloaded. If we were to travel with all 4 tanks full, we'd be more than 1,000 lbs over the GVWR. I am not going to do it. If you really want to and your trailer is still under warranty, I would see if your dealer will give you something in writing that will cover a crack or failure if you tow with one or more full tanks. I doubt they will do it. The first thing Lippert will try and say is that you overloaded your frame and walk away from it.

For those that insist that trailers should be and are built to handle the weight of water, then you would do good to start reading all the posts you can find on the various RV forums out there about owners who have had cracked frames, failed welds and broken tank support straps from overloading their trailers. It happens a lot more than people realize. Frames these days are being built on the thin edge of barely being able to support just the UVW. Frames typically aren't even I-beams anymore, they're 3 pieces of sheet metal welded together to look like an I-beam and they flex like crazy. If you knew what your frame was really like, I doubt that anyone would think it was no problem.
jamesu
Explorer
Jul 04, 2013
You say you new so here's my procedure when dumping the tanks. Probably everybody does this but since you're new here goes. Dump the black water first. Then close the black water valve and open the grey water valve, cleaning out your sewer pipe of the black water crud.
Huntindog
Explorer
Jul 03, 2013
Searching_Ut wrote:
I've always pretty much figured the tanks are there because you couldn't hook up where you were camping, and thus must travel with the stuff on board. Most of our camping is in remote forest service/blm etc campgrounds where at best you'll have a pit toilet in the campground, and maybe a water spigot. Dump stations are rare.

To be honest, even in trailers I've had with underpowered trucks, I never noticed any significant MPG or handling differences between traveling tanks full, or tanks empty. My current TT has 2 40 gallon grey tanks and 40 for the black and even when they are fairly full I don't seem to notice any difference even on long mountain dirt roads.

X2
My TT has two 42 gallon grey tanks and two 42 gallon black tanks. Along with a 42 gallon fresh + 12 gallon HWH.
It is not uncommon for us to travel home up to 500 miles with full tanks. Since we are traveling with animals it is much easier to just take care of it the next day after getting home.
Haven't noticed a difference MPG wise. Wind resistance is bigger factor than weight...So long as the TV is capable of it.

As a aside. All that sloshing around really breaks things up. My sensors never give a bit of trouble.

IMO, The worst thing you can do to your sensors is dumping without a good long tow.. Across the campground to the dump station doesn't count.:B
Searching_Ut
Explorer
Jul 03, 2013
I've always pretty much figured the tanks are there because you couldn't hook up where you were camping, and thus must travel with the stuff on board. Most of our camping is in remote forest service/blm etc campgrounds where at best you'll have a pit toilet in the campground, and maybe a water spigot. Dump stations are rare.

To be honest, even in trailers I've had with underpowered trucks, I never noticed any significant MPG or handling differences between traveling tanks full, or tanks empty. My current TT has 2 40 gallon grey tanks and 40 for the black and even when they are fairly full I don't seem to notice any difference even on long mountain dirt roads.
dadmomh
Explorer
Jul 03, 2013
It's a rare day when we travel with much of anything in the tanks. It all =s weight, which =s even worse fuel mileage. Water weight 8.3# per gallon, so just do the math x the number of tanks. If you're in a spot where it's impossible to dump, many of the state roadside rest stops have dumps and there's a sign posted to that effect. Watch for Pilot/Flying J truck stops or Love's. They usually have dump stations. If you just walk in and ask about dumping, they will usually tell you it's $x, but if you invest in a coke or some snacks and then ask, most often the price is $0.
Atlee
Explorer II
Jul 03, 2013
Yes, Skyline is certainly still in business. Layton, Koala, Walkabout, etc are a few of their trailers.

However, I was completely wrong about any Skyline trailers and being cautioned against traveling with full black and/or gray tanks.

Skyline does not caution against this.

Huntindog wrote:
Atlee wrote:
Skyline RV advises against traveling with full black & gray tanks. They advise to dump as soon as posible.

hershey wrote:
You should be able to tow easily with holding tanks full or nearly full. Actually, the travel motion will facilitate the breaking up of any solids and make the next dump much more efficient. Most campgrounds will allow passing through RVers the use of the dump station for a fee. Many truck stops (Old Flying J's) have a dump station, most charge a small fee. Some road side parks have a dump station but those are rare. Some RV dealers have a dump station also. There are apps for your smartphone that shows dump locations.
Is Skyline still around?

No matter. ANY TT that cannot be towed with full tanks has a design flaw.

The only reason this subject should have any merit is for those with a marginal TV who need to watch the weights very closely.