How to know if fresh water tank is full?

[CJW8]

New 5th wheel toyhauler has 90+ gallon fresh water tank. The under belly is enclosed so I cannot see the tank. The tank gauges are inside the camper but they are notoriously undependable and even if they work properly they only give you 4 points of resolution.

How full can you get them? Till it comes out the fill vent? I am tempted to fill till gauge says 3/4 and slow fill rate to a trickle till it comes out the vent. Will wait to see what others do.

[allen8106]

Most have an overflow. It's full when water comes out the overflow.

[GPG52_]

We purchased a "Digital Electronic Water Smart Flow Meter for Garden Hose Watering" for about $15.00. You can get them at most garden or hardware store.
Amazon also has them.
You install it between the water spigot and your potable water hose.
With the meter and knowing the size of your tank you can gauge how much you put in your tank... fill it up, half a tank, 15 gallons if you just want a little for travelling purposes etc.
For those who are water conservationist you can also gauge how much water you use during your stay.
This works great for us.
GPG

[CJW8]

With the power fill, where a hose is attached to a hose fitting in a compartment, I'll have to look to see where the overflow is located. It will be a couple of weeks till I can get back to my camper.

Thanks for all your responses.

[AZ_T_T]

Dtank wrote:

Arcamper wrote:
Our new Montana has a power fill only water tank and I try to check the gauge and stop at full but twice now I missed it and it started coming out of the vent. Montana says not to do this or damage can happen. I guess if you put water in faster than the vent can let it out you could over pressure the tank and burst it.

I slow it down now when its about 3/4 full.

Good plan........

Know the flow! - - especially using campground supply.
Some of 'em put out a LOT of volume!

*If* you must use an exterior *connection* to the RV, you may not know just what kind of quantity you are getting.....if you didn't check.

So check the campground hose bib - one turn gets you......
two turns, etc...;)

.

I also had 2 pex lines and both were over flow lines. I just tied them together with a T fitting and then out to the spigot.

Good luck!

[waltbennett]

I'll fill all the way ONLY when dry camping. If going to a CG, I'll only put enough in to flush the toilet & wash hands a few times. Our fresh tank is at the tail end of our Monty, so that weight seriously affects pin load, unless there's a whole lot of weight up front. And it also does affect mpg - about one more mgp without it all. That's about an 8 percent change.

[Dtank]

Arcamper wrote:
Our new Montana has a power fill only water tank and I try to check the gauge and stop at full but twice now I missed it and it started coming out of the vent. Montana says not to do this or damage can happen. I guess if you put water in faster than the vent can let it out you could over pressure the tank and burst it.

I slow it down now when its about 3/4 full.

Good plan........

Know the flow! - - especially using campground supply.
Some of 'em put out a LOT of volume!

*If* you must use an exterior *connection* to the RV, you may not know just what kind of quantity you are getting.....if you didn't check.

So check the campground hose bib - one turn gets you......
two turns, etc...;)

.

[Stefonius]

ford truck guy wrote:

AZ T&T wrote:

Stefonius wrote:

Lantley wrote:
If I don't use the gauge and fill till it over flows than a siphon will start and my tank will drain itself onto the ground.

I have that problem too, and it makes me insane! I fill the tank until it starts to come out of the overflow, but then if the rig is tail down at all while setting up, it will siphon the tank dry and I can't stop it. Very frustrating when I'm boondocking, as I usually have to set up the RV nowhere near a spigot.

The only thing I can think to do is to plumb a shut-off into the overflow so that I can stop the tank from self-draining until I get level.

I had that problem also, I solved it by extending the over flow tube to the side of the FW and adding a small spigot.

I did this exact same thing... went to Home Depot and got the fittings needed.. I also diverted the drain line to the side of the camper...It got old laying down and crawling under the axles to turn the drain....
I keep the overflow vent spigot open at all times.. except directly after filling to break the siphon./..

Excellent! When I posted earlier, I figured the response would be one of two things... Either "That's what I did and it works great", or "Don't do it - your fifth wheel will spontaneously explode like a nuclear bomb". I'm very happy to know that it was the former and not the latter. As soon as I figure out which of the two identical PEX lines is my fresh water tank overflow, I'm putting a valve in it. Thanks to AZ T&T, I'll also be putting the valve at the edge of the rig so I don't have to lay down under it. That had not even occurred to me before.

I love this forum!

[Pangaea_Ron]

My manual says to fill the tank until a bit comes out the overflow. When that happens I occasionally have a suction form, which can drain quite a bit of water out of the tank.

Fortunately I can see my translucent tank from a basement storage bin, and can see the water level and turn off the water when the tank looks full.

[laknox]

CJW8 wrote:

rr2254545 wrote:
Your tank holds right at 500 lbs of water - this surly is a lot to carry around

More like 776 LBs. 8.345 LB/ gallon @ 93 gallons.

Since TH's are most likely used while boondocking, it =better= be designed to travel with full a full water tank AND a full gas tank, assuming you have one. I'm a fill it 'til it overflows guy. I used to have a short fill hose, but it disappeared somewhere along the way and I've never replaced it. Turn the hose on about 1/2 and fill it. I have to be real careful up at the Shell at Camp Verde as they have LOTS of water pressure, so I have to baby it to be sure it stays on and doesn't go too fast. (We fill up there on the way to our usual boondock site, about 30 miles further N.)

Lyle

[ford_truck_guy]

AZ T&T wrote:

Stefonius wrote:

Lantley wrote:
If I don't use the gauge and fill till it over flows than a siphon will start and my tank will drain itself onto the ground.

I have that problem too, and it makes me insane! I fill the tank until it starts to come out of the overflow, but then if the rig is tail down at all while setting up, it will siphon the tank dry and I can't stop it. Very frustrating when I'm boondocking, as I usually have to set up the RV nowhere near a spigot.

The only thing I can think to do is to plumb a shut-off into the overflow so that I can stop the tank from self-draining until I get level.

I had that problem also, I solved it by extending the over flow tube to the side of the FW and adding a small spigot.

I did this exact same thing... went to Home Depot and got the fittings needed.. I also diverted the drain line to the side of the camper...It got old laying down and crawling under the axles to turn the drain....
I keep the overflow vent spigot open at all times.. except directly after filling to break the siphon./..

[AZ_T_T]

Stefonius wrote:

Lantley wrote:
If I don't use the gauge and fill till it over flows than a siphon will start and my tank will drain itself onto the ground.

I have that problem too, and it makes me insane! I fill the tank until it starts to come out of the overflow, but then if the rig is tail down at all while setting up, it will siphon the tank dry and I can't stop it. Very frustrating when I'm boondocking, as I usually have to set up the RV nowhere near a spigot.

The only thing I can think to do is to plumb a shut-off into the overflow so that I can stop the tank from self-draining until I get level.

I had that problem also, I solved it by extending the over flow tube to the side of the FW and adding a small spigot.

[Stefonius]

Lantley wrote:
If I don't use the gauge and fill till it over flows than a siphon will start and my tank will drain itself onto the ground.

I have that problem too, and it makes me insane! I fill the tank until it starts to come out of the overflow, but then if the rig is tail down at all while setting up, it will siphon the tank dry and I can't stop it. Very frustrating when I'm boondocking, as I usually have to set up the RV nowhere near a spigot.

The only thing I can think to do is to plumb a shut-off into the overflow so that I can stop the tank from self-draining until I get level.

[Ozlander]

rr2254545 wrote:
Your tank holds right at 500 lbs of water - this surly is a lot to carry around

That Jeep and tow bar weight right at 5000 lbs.
That's a lot to be towing around.

[AZ_T_T]

I also fill my FW until it burps or trickles out the overflow. My Jayco has a 92 gallon capacity that is split between 2 flat tanks. I've found that if I turn the water off for a few minutes after it first burps the water will equalize between the tanks and I can add another 10 or 12 gallons.