I'm on my first RV trip and I'm trying to figure out what I'm doing wrong. I filled the water tank full this morning and drove all day. About halfway i noticed water draining out of the overflow tube underneath. By the time i got to my destination, the water tank was completely empty. Is there some kind of valve I need to close so that it won't keep draining the water out? I checked the manual but it makes no mention of this. It's a Triple E topaz 25 ft 5th wheel.

Unfortunately on many rv's the overflow is plumbed in such a way that once it starts to drain for any reason such as sloshing as you go around a corner, it creates a vacuum and can empty the entire tank. For now your best bet is to plug the drain but don't forget to remove the plug when filling the tank. The correct fix is to find the overflow line and loop it upwards above the tank then down.

I'm thinking what you see is the low point drain not a tank overflow. There will be a shutoff valve for the low point drain and the location should be in your manual in the section how to winterize your fresh water system.

Make sure that the tank drain valve is closed.

Yes, the tank drain valve. That's what I'm trying to find. I've looked at the paper manual, and the online PDF manual, but the only mention they have for the drain (even after text searching the whole document) is:1. Drain the fresh water tank.Nothing about how that's supposed to happen, or where the actual valve is :/

I'll offer this has a suggestion. Look on the inside trailer floor directly above where the water is draining. Look for a cutout in the floor and left in place so it's not very noticeable. (in my trailer it's a 5 inch circle with a small hole for my finger to lift up the floor cutout).

Water keeps draining out of the overflow | Good Sam Community

17 Replies

wa8yxm
Explorer III
Jan 19, 2017
I do not think they put it in my manual either.. I think different serial numbers of the same make and model.. Well they may have different tanks and thus put the valve in different places.

But one HINT.. the OVER FLOW.. is well.. OVER

your problem was "under".
DrewE
Explorer III
Jan 19, 2017
ksten wrote:
Found it. It was in the compartment behind the 5th wheel attachment.

Strange they never put it in the manual...

Glad you found it.

RV manuals tend to be very generic, though that does vary somewhat with different makers. It may be strange, but it's hardly surprising to me that they didn't have information on where valves etc. are located.
ksten
Explorer
Jan 19, 2017
Found it. It was in the compartment behind the 5th wheel attachment.

Strange they never put it in the manual...
wa8yxm
Explorer III
Jan 19, 2017
The overflow tube is not UNDERNEATH the tank drain however

You forgot to close the drain valve. (or install the drain plug depending on the RV) this is there so you can drain the tank at the end of the season to prevent freeze damage.
RedRocket204
Explorer
Jan 18, 2017
Then it is obviously your fresh tank valve that is open.

My trailer fresh water tank has a gate valve that you reach from under the trailer. You pull the gate and watch out for the rush of water :)

This video shows a RV fresh water tank that exists under the bed where the fresh water tank valve is very close to the tank, but then plumbs to the outside, maybe this is similar to what you have???

youtube - Rv Freshwater tank drain

Another video with a different valve location - youtube - WNY RV Rental - Sunseeker: How To Drain The Fresh Water
ksten
Explorer
Jan 18, 2017
I just tried filling it again and it drains immediately, so there has to be a valve somewhere. The question is where...
hotpepperkid
Explorer
Jan 18, 2017
Mine did the same thing although it didn't empty the tank but water did slush out of the over flow so I put a 1/4 turn valve on it.
drsteve
Explorer
Jan 18, 2017
A quick Google search reveals that Triple E puts the valves inside the storage compartment aft of the entry door. Look for a knob-style shutoff. Overflow might run through that area too.
dewey02
Explorer II
Jan 18, 2017
RedRocket204 wrote:
When you filled your fresh water tank, was there water immediately flowing onto the ground from somewhere under the trailer? If not and the water only came out after you were moving, then your fresh water tank drain valve is closed and the advice given about the vent creating a vacuum is what you should be looking into.
x2
RedRocket204
Explorer
Jan 18, 2017
ksten wrote:
Yes, the tank drain valve. That's what I'm trying to find. I've looked at the paper manual, and the online PDF manual, but the only mention they have for the drain (even after text searching the whole document) is:

1. Drain the fresh water tank.

Nothing about how that's supposed to happen, or where the actual valve is :/

When you filled your fresh water tank, was there water immediately flowing onto the ground from somewhere under the trailer? If not and the water only came out after you were moving, then your fresh water tank drain valve is closed and the advice given about the vent creating a vacuum is what you should be looking into.