How Do I Know When My Tanks are Full?

The easiest way to tell if the black tank is full is to shut off the water and look down the toilet. There's usually about 6" of air space between the top of the liquid and the floor when it's full.

When the gauge says full DUMP. It's not worth it to find out the hard way you have a leaking connection between the toilet and the tank. We found out the hard way comming home from the Winnebago Grand National Rally one year. The tank was only about 1/4 full because we had it pumped while at the rally. When we left there was a long line of coaches waiting to dump. Since ours was almost empty and we could get home in a few hours we decided to dump at home.

When we pulled into the drive at home and got out there was an awful stench and goo running out of the rear of the motorhome. Apparently the pumper truck had partially collapsed the black tank and the connection to the toilet came apart. The sloshing for a few hundred miles had spread sewage all over the tank compartment and it was running down the side of the motorhome.

It took several hours of serious cleaning and removing access panels to get out all the crud. It cost another $250 to have the tank connections repaired. Now we always dump before we hit the road, even if there's only a few gallons in each tank.




As far as the grey tank is concerned we had the water come into the shower once. I took a 5 gallon bucket and went outside to the dump valves. I opened the grey tank valve and filled the bucket then went back in and dumped it in the toilet.

hershey wrote:

The gauges on the tanks were designed by an evil mind who gets great satisfaction in having RVers spend hours and money on trying to get them to work.

To this I heartly agree!

In my coach, the kitchen sink also goes to the black tank and not the grey so it is the one that normally fills first. That makes it easy as all I have to do is look down the toilet and look at the level. Someday, I will deal with the level lights that occasionally do something.

I do agree with the above statement about not over filling as a loose connection on the top of the tank is not normally an issue, but will rapidly become one if you fill to the absolute top. We have enough issues with these coaches without creating more!

Just count the days. I know that when boondocking, I can go 7 to 9 days with GI showers and being careful with my water demands before the gray tank needs emptying. I know that all dishwater and portable water can be dumped into the black tank and never worry about filling it before the gray tank fills.
The gauges on the tanks were designed by an evil mind who gets great satisfaction in having RVers spend hours and money on trying to get them to work.

Fill grey tank until it says full.

Then start filling grey tank from the shower only. Se how long it takes for it to back up to the shower 5, 10, 15, 20 minutes?

Then you will have an estimate of how much margin is left. Right now you have no idea if the full sensor was placed appropriately or inappropriately. Check it and then decide how bad full really is in your MH (Not some other forum posters MH)

We used to let it back into the shower once in a while and weren't too concerned as long as we were sitting still. UNTIL we realised that it hadn't done that in a while and the bathroom floor was wet. Thought it was a leaking toilet. NOPE! Broken shower drain. :S The water didn't get high enough to flow into the shower, it just poured out the bottom, some getting onto the floor. Luckily no floor damage but replacing the shower floor and drain was pricy and a pita for the techs!

TennTechMan wrote:
Is it common for people to continue using the water until it starts coming up the shower drain?

Not if they have common since. :B

There is an added danger to the full gray tank. You know it overflows into the shower, but if you aren't using the shower and are running water in the sinks you could potentially fill the shower pan and overflow onto the floor. You also want to make sure you don't drive if you max it out, because the sloshing around may send it up the shower too.

You can crawl under the motor home and see the 4 connections on the side of the tank for the level indicators. The top one is the "full" connection. The distance from the top connection to the top of the tank will give you an idea of the capacity when full.

When the toilet 'burps'....black tank full....dump it.
When sink or shower starts draining slower.....grey tank full....dump it
When on-board pump goes 'buurrrrrrrpp'....should have filled fresh water tank because now you have to go do it in the dark

TennTechMan wrote:
I have a 1996 Winnie Brave 33'. It's got "Levels Test" board on the wall. There are only 4 indicators for each level. Best I can tell, they work correctly.

My real question is this, when the grey water (or black for that matter) shows all 4 LED's illuminated, is there any capacity left? Is it common for people to continue using the water until it starts coming up the shower drain?

Our indicators seem to work really well. They can show all the way full and we still have a little more room. I had the grey tank start coming in the shower once. We have a 70 gal. grey tank and I guess I wasn't monitoring as close as I should.

Our toilet is an electric macerator toilet and it has it's own monitoring panel. When it's about half full the green light will turn yellow and then when it's close to full , it will turn red and will not flush unless you hold the button for six seconds to force a flush. We never let it get that full.

After a little practice, you will find out how accurate your monitoring system is.

MM.