Towing with Tanks full or nearly full.

[GSGRAPE]

I have a question about towing with holding tanks and fresh tank full or nearly full. I have owned RV's for 25 years and have towed several times with the fresh tank full, and have also towed with holding tanks full when no dump station was available. I have never had a dealership or sales person say you can not tow when tanks are full. That to me would defeat the purpose.

The reason I am asking is because I recently moved my son's rv from Texas to North Carolina and we hit a bump on a bridge in Louisiana and the black tank fell out. The RV is a 2017 and just over a year old by a month. We thought we had emptied the tanks but in the process of getting on the road I guess we forgot the black tank. But I don't feel that should make a difference.

Looking for imput on this.

 

[Garypowell]

I have always emptied my tanks more from a travel weight consideration. Once or twice, like you, I leave water/stuff in them because of no sewer facility where we were leaving. But always when in that condition I drove slower and with more caution.

I thought I would check my trusty owners manual. While the departure check list just ask you to check the level of the tanks back in the "plumbing" section under Black Water Holding Tank is says about emptying..."do it frequently and especially before travel".

I know from being on this forum for years that some drain and some travel full....especially fresh water. Others have reported a shifted or dropped tank.

 

[ram22]

Holy crap! Excuse the pun. I never even thought of that.


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[danemayer]

There are bumps and then there are bumps. There's also speed. The faster you're going, the greater the force applied to the trailer when a bump is encountered.

You didn't mention what RV your son has. Different Heartland models may use different tank mounting arrangements and if not a Heartland RV, who knows how it was mounted.

At about 8 lbs per gallon, a nearly full 45 gallon holding tank weighs about 360 lbs. Hit a bad enough bridge joint at 70 mph and you might break whatever supports are holding the tank.

On our 2011 Landmark, the Gray #1 tank is under the black tank, and is held by angle iron running between the frame members. However, the angle iron is attached to the frame members with 2 screws on each side. The screws are the weak link on our trailer. On newer large Heartland RVs, I think the supports may be attached to the frame more securely.

 

[porthole]

If I had to guess I would say we leave home 80% of the time with a full load of water (120 gallons)
I would also guess that we travel with the waste tanks with whatever quantity of waste accumulated during the camp trip’s time.

If the campground doesn’t have a sewer hookup I will usually wait till I get home to dump.

 

[ram22]

There are bumps and then there are bumps. There's also speed. The faster you're going, the greater the force applied to the trailer when a bump is encountered.

You didn't mention what RV your son has. Different Heartland models may use different tank mounting arrangements and if not a Heartland RV, who knows how it was mounted.

At about 8 lbs per gallon, a nearly full 45 gallon holding tank weighs about 360 lbs. Hit a bad enough bridge joint at 70 mph and you might break whatever supports are holding the tank.

On our 2011 Landmark, the Gray #1 tank is under the black tank, and is held by angle iron running between the frame members. However, the angle iron is attached to the frame members with 2 screws on each side. The screws are the weak link on our trailer. On newer large Heartland RVs, I think the supports may be attached to the frame more securely.

Airliners 'hit bumps' with full potable water and holding tanks and they don't fall out. I think they're stressed to withstand 2.5 G's. RV manufacturers should be strengthening these tank mounts similarly. If not, they should at least be testing them to failure and specify that in the Owners Manual as a limitation, not just 'it's a good idea to dump your holding tank before travel.'


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[danemayer]

Airliners 'hit bumps' with full potable water and holding tanks and they don't fall out.

Maybe Boeing will start building RVs.

 

[travelin2]

Always fresh water onboard, anywhere from half to full depending on destination.
Gray tanks may be or not empty depending on last emptying. We don’t always request or require FHUs.
Black tank will have at least 12-15 gallons even if it was just emptied and flushed. Always recharge with water so solids are swimming, not sitting on the bottom.
Although I’ve spoken to others who have lost a tank, it’s never been a HL unit.


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[RoadJunkie]

Heartland specifies the tank capacities for fresh water and holding tanks. There is nothing written that specifies the rig will hold those amounts while traveling.

 

[danemayer]

My 2011 Heartland Trailer Manual says:

Do’s and Do Nots of Holding Tank Use

DO – Clean the holding tank with an approved cleaner.
DO – Add a special chemical additive to sanitize and improve tank action.
DO – Guard the tank against freeze-up.
DO – Keep the waste water tank dump valves closed to allow the tanks to get as full as possible to facilitate drainage.
DO – Keep the dump valve closed and the drain cap in place to allow use of the system when not parked at a campsite.
DON’T – Put facial tissues, paper, automotive type antifreeze, sanitary napkins, diapers or household toilet cleaners in your holding tank.
DON’T – Put foreign objects in the system that could clog or damage it in any way.
DON’T – Travel with full holding tanks.

 

[jnbhobe]

I always travel with full water, always have something in the black and gray too.

 

[TravelTiger]

Someone touched on it earlier, but here's the thing. Your rig has a limited carrying capacity. If you're fairly heavily loaded, you may be close to your GVWR. Then if you add the weight of full fresh water or full waste tanks, you could be over your GVWR. Many folks are over just with their "stuff" -- so we make a point to try to travel empty, to be the lightest weight possible. Dumping tanks is easy, dumping "stuff" is hard. Lol!


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[SNOKING]

Maybe Boeing will start building RVs.

They have built boats in the past, so it is not that big of a stretch. Chris

 

[NWILSON]

At about 8 lbs per gallon, a nearly full 45 gallon holding tank weighs about 360 lbs. Hit a bad enough bridge joint at 70 mph and you might break whatever supports are holding the tank.

They reduced the risk on our new Cyclone....waste tanks are only 34 gallons!

 

[porthole]

They reduced the risk on our new Cyclone....waste tanks are only 34 gallons!

I don't get that.
I see that the black tanks are still 40, but making the tanks that need to be bigger 15% smaller is absurd. I would think with as small as they made all the basement storage areas that bigger holding tanks will be in place.

- - - Updated - - -

My 2011 Heartland Trailer Manual says:


Do’s and Do Nots of Holding Tank Use

DON’T – Travel with full holding tanks.

Makes me think of two things.

1st, glad I didn't get an owner's manual to see I might have been breaking the rules for the past 8+ years.

2nd, glad to know our fire engines don't have these limitations of traveling with a full holding tank.

And before I get countered with "but fire engines are designed to carry water in their holding tanks" why should it be any different with the "holding tanks" in our RV's

 

[danemayer]

They reduced the risk on our new Cyclone....waste tanks are only 34 gallons!

Current specs on the CY 4150 below. I suppose if you have 2 gray tanks, they'd each be 34.5 gallons. But some of the toy haulers have plumbing set ups different from the rest of us.

Fresh Water

100 gal​

Gray Water

69 gal​

Black Water

69 gal


​

 

[porthole]

Current specs on the CY 4150 below. I suppose if you have 2 gray tanks, they'd each be 34.5 gallons. But some of the toy haulers have plumbing set ups different from the rest of us.

Fresh Water

100 gal​

Gray Water

69 gal​

Black Water

69 gal


​

2 water tanks - combined with a crossover hose
2 gray water tanks - one for shower and bathroom sink, one for galley sink
2 black water tanks - one for forward bath toilet, one for rear bath toilet and sink

I would guess Neale's point is his last toy hauler as well as ours had/has 40 gallon waste water tanks.

 

[cjb2283]

I have also read somewhere that some people prefer to travel with full tanks to lower center of gravity of their rig. Obviously this helps in windy areas/conditions to reduce in sway and/or rollovers. I do a lot of boondocking, so I travel to the site with full fresh and if there isn't a dump station that isn't packed on the way I will travel home with tanks close to full if not full. Since my fresh tank is further forward (forward of axles) than my grey/black (which are behind the axles) I try and have as much water in the fresh as possible. (Sometimes I carry two 35 gallon water jugs to fill it up with, depending on length of stay.) If my fresh is empty/near empty and my grey/black are close to full I get a lot of bucking/chucking over bumps due to weight distribution. The problem I see now knowing that 'fallout' could happen, I can't easily inspect my tanks and hangars due to the enclosed underbelly.

 

[Bob&Patty]

Dan, LOL on Boeing. Problem being our BH does not fly at 40K' and 500 MPH. The OL' GMC ain't that good, don't know about your Dodge???

 

[JohnD]

I like to keep the weight down so travel with usually no more than 1/3 tank of fresh water so we can use the facilities while rollin’, and the sewer tanks as empty as possible.

I have filled the tanks for ballast during high wind storms while camping to keep from blowing away.