Road trip: how often to dump tanks?

[amarie1]

Hi! I’m on day 3 of an 8 day road trip, driving about 5 hours a day and staying mostly in Rv parks. Some have city water, others I use my freshwater tank. 
 

Im driving solo in a 30 foot motor home. Should I be (do I need to) dump my tanks every day, before I leave to drive another 350 miles? Or should I wait until they’re half full or so. I am careful to add water when I flush, and I toss paper separately.

thanks

[Chalkie]

Generally speaking you can dump the grey tank whenever you want, however, always make sure the black tank is at least 2/3 full before dumping. You need that amount to insure that the flow will take the solids with it. 

When we are stationary I will leave the grey tanks open all the time and dump black only when nearly full. When traveling I will empty the grey, if convenient, before we hit the road simply to get rid of the added weight of the water but always follow the rule on the black. 

Also we only fill up the fresh water tank when we know we are going to need it, such as going into an electric only campground. Otherwise we keep just enough for toilet flushing, again to hold down weight.

[amarie1]

Ok, thank you Chalky. 

[durangodon]

Not saying any other method is wrong, but I have a bit of a different take on this.  I say it really depends on how the tanks are constructed and mounted.

I've seen black tanks which were built out of thin, flexible plastic and mounted with a couple of metal straps.  This is very typical of less expensive units.  I made a point to never travel with much product in these tanks.  The constant sloshing of liquid and solids in such a tank flexes the plastic and can and does cause stress cracks and breaks in the tanks, particularly where the straps contact the tank.  A 40 gallon tank with 30 gallons (250 lbs.) of product sloshing around can be really stressful on the tank.

On the other hand, if the tank is heavily built and supported in a better manner, such as in an enclosed metal and insulated case, it's more likely to withstand such sloshing abuse without damage or stress.

Anytime I dumped the black tank and it was not almost full, I just gave it a good flushing to make sure all solids got out. 

 

[amarie1]

Hmm. I do not know about the construction or mounting of them. 

[Kirk W]

We do as Chalkie does, pretty much. Often you can save a few bucks per night by not getting a sewer connection since most parks have both full hookup and water/electric only.  On the cheap tanks, I would rather take a chance on traveling with a little in the tank than to deal with a collection of solids in it. Also, I have never seen tanks in a motorized RV of the type he is cautioning you about. 

We usually travel with the fresh water tank about half full, but with any tank part of the issue is the size of the tanks. When we had an 80 gallon potable water tank I rarely filled it more than half full, now that we have a 30 gallon potable water tank I seldom let it get below that point. 

[durangodon]

22 minutes ago, Kirk W said:

On the cheap tanks, I would rather take a chance on traveling with a little in the tank than to deal with a collection of solids in it. Also, I have never seen tanks in a motorized RV of the type he is cautioning you about. 

I agree.  I would never leave a tank dry.  Always put a small amount of water in after a good flushing.  That's not the same as traveling with a half full tank.

I've had the covers off of holding tanks before on brand name motor homes.  You might be surprised how flimsy some of them are mounted.

If I don't know how well they are mounted and built, I prefer to use caution.  It doesn't take but a few minutes to dump and give a good flushing before traveling, especially if you use plenty of water in the toilet bowl while parked.  If I'm going to be stationary for a while, I never dump until the tank is almost full.

[Star Dreamer]

We try to empty our tanks every couple of days but can go longer if needed. Weight is a concern. I however do not drain my Grey water tanks until after I have drained my Black tank so that I can use the grey water to help flush the drain hose.

[2gypsies]

With boondocking for two weeks' time, naturally both tanks are full when we leave.  We may drive many miles before finding a dump station.  Never an issue.

[sandsys]

8 hours ago, amarie1 said:

Should I be (do I need to) dump my tanks every day, before I leave to drive another 350 miles? Or should I wait until they’re half full or so. I am careful to add water when I flush, and I toss paper separately.

Wait. You want your tanks full enough to flush well. That means the black tank needs to be more than half full and the gray tank needs to have enough in it to flush the hose after flushing the black tank. That said, our rigs, except the one we only kept 4 months, always had enough carrying capacity to manage that weight. The people who only fill their fresh water half full tend to have huge tanks. My van had 40 gallon fresh and 20 gallons each black and gray. I only had to fill the fresh tank every other dump and I rarely dumped more than once a week and sometimes went two weeks between dumps.

Linda

[Pat & Pete]

I have three valves on our Monaco . Grey , black and a final valve before the hose .

I open the final , then dump the black . Once empty , I close the final valve and open the grey and let the tanks equalize . Then pull the final . Sometimes I close the black valve before it's empty , as it's not a bad idea to leave some in the black tank when driving . It helps .

I always close all valves when not dumping . No need to leave the door open for unwanted sewer critters .

[amarie1]

Thanks all. Question for @Pat & Pete: why if ever would someone leave valves open?

[Pat & Pete]

5 minutes ago, amarie1 said:

Thanks all. Question for @Pat & Pete: why if ever would someone leave valves open?

Maybe because they are lazy and can't afford an extra couple minutes and the 'long' walk around the rig to do it right .

Some like to leave the grey valve open , but , unless you filter what goes down any drain , there can be build up in that tank , too .

Not to mention they probably don't think about what might crawl through those open valves .

Just remember : Every thing/action has a price and it will be paid .

[mptjelgin]

1 hour ago, amarie1 said:

Thanks all. Question for @Pat & Pete: why if ever would someone leave valves open?

 

1 hour ago, Pat & Pete said:

Maybe because they are lazy and can't afford an extra couple minutes and the 'long' walk around the rig to do it right .

Not to mention they probably don't think about what might crawl through those open valves .

Maybe it is because their experience over many years of fulltiming indicates that leaving the grey valve open works just fine, and is more convenient over a period of weeks or months. What exactly do you think is going to "crawl through those open valves" from an individual septic tank and drain field, which is the case at the vast majority of places that we've stayed?

Amarie1 - You will find what works for you as your travels continue. If you are staying in parks for a few days at a time, dumping occasionally will work fine and you may not ever have a desire to leave the grey valve open.  But if you stay in a location for a longer period of time, you may find that leaving the grey valve open is more convenient. It has nothing to do with being lazy.  Just individual experience and preference. 

Edited August 15, 2020 by mptjelgin

[Bill Joyce]

We were fulltimers for 15 years and are now parttimers and we leave the grey tank valve open until a couple days before we dump the black tank.  No problems.

[Randyretired]

I dump our black tank once a week.  Since it is 70+ gallons it probably isn't 1/2 full.  I don't like to hit our septic with more than that at a time.  We are also in a spot that I have to use a macerator.  When we move I will add a few gallons of water with detergent to get the worst from tanks at next dump.  I alternate leaving the grey tanks ( two 45's) open.  I will leave them open for a period then close them for some time This has worked well for us.  

[mptjelgin]

28 minutes ago, Randyretired said:

 I alternate leaving the grey tanks ( two 45's) open.  I will leave them open for a period then close them for some time This has worked well for us.  

I do close my grey water valve once a month(ish) to get a good "flush" from the tank and through the line periodically.  Beyond that it is left open. 

[amarie1]

Okay but you're all talking about leaving the grey valve open while you're connected to a sewer, right? 

[mptjelgin]

Correct. Don't open either of the valves unless you are hooked up!!

[2gypsies]

Grey tanks collect soap scum, grease, perhaps coffee grounds and food particles.  If you leave the valve open all the time a lot of that is not washed away by the little trickles of water going through.  The grease and scum can collect the other stuff and just stay at the bottom of the tank.  It can also collect inside the sewer hose and around the seal.  By leaving the grey valve closed until full or nearly full, when you do empty there's a big swish and movement of the contents and it just keeps the tank cleaner.

Sometimes after emptying the grey and black and moving on, we'd fill the grey and black with 1/2 a tank of fresh water and a little Dawn and then do our driving thinking that this movement would do a little more cleaning.  Tanks will never be completely clean no matter your routine.  You can just help a little.  We'd then dump it right away when we were at our next site or nearby at a dump station if going to a boondocking spot.  I don't know if it helps but it made us feel better. 😉

Some rely on emptying a bag of ice cubes in the tank before moving on thinking that will clean it.  There's a video experiment out there debunking this practice.

https://www.thefitrv.com/rv-tips/do-ice-cubes-in-the-rv-black-tank-really-work/

The above link has a search bar for many more interesting topics this guy experiments on.  Put in 'black tanks' and see them.

Edited August 15, 2020 by 2gypsies

[durangodon]

25 minutes ago, 2gypsies said:

Some rely on emptying a bag of ice cubes in the tanks

How does one empty a bag of ice in the gray tank?

Edited August 15, 2020 by durangodon

[kmessinger]

""Dump early . . . dump often."

[2gypsies]

2 minutes ago, durangodon said:

How does one empty a bag of ice in the gray tank?

Should have been 'tank' as in black tank.  Sorry.

[sandsys]

It appears to me that people who leave their gray tanks open are parked long term and many have a washer on board so the hoses get cleaned with every load of laundry. Doing laundry with closed valves could be an "interesting" experience. 

Linda

[Kirk W]

2 hours ago, kmessinger said:

""Dump early . . . dump often."

Not a good plan for your black tank and questionable for the gray. In either case you will slowly fill the tanks with solids and sludge that need the rush of fluid of a half or more full tank to carry that out.