Black Tank Number of Days

[Ski]

We are going back on the road. Looking at a 40' Mountain Aire. Black tank holds 45 gal, gray 65 gal and fresh gal 105. Our previous RV was a New Horizons 5th. which held 70 gals each fresh, gray and black. We were very pleased with the capacities.

 

Question is holding only 45 gal black, for the average couple, about how many days can we go without dumping?

 

Thanks,

 

Al

[skp51443]

With care two weeks was no problem for the two of us with a 45 gallon black tank and two 45 gallon gray ones.

[Dennis M]

Our Mountain Aire fiver has 75 fresh, 87 gray, and 55 black. The gray is split between a small (25 gal?) kitchen and a larger shower tank.

 

When we are without hook-ups we use paper plates, wash dishes in a dish pan and dump it in the black tank. This balances things out. The last 6 weeks has been our first long term experience with just water and elec. and we have been dumping every 5-6 days. Taking navy showers, but using the toilet pretty much as normal.

[Devilishjim]

Our 40 gal black tank lasts us 6-7 days and we give a royal flush to be sure to have plenty of liquid in the tank

[SpaceNorman]

I've never had the opportunity to figure out what sort of cruising range we get on our black tank ... we fil the 60 gallon gray tank long before we come close to filling the black tank. ... and if I'm gonna dump one ... I'm dumping both!

[2gypsies]

We had 45/65/105 and could last 12 days boondocking. That's without dumping any grey on the ground.

[richfaa]

With just the two of us the longest we have ever been at a no hook up site was at a couple of rallies and we went 5 days with no problem with the black tank.

We are rarely at a no hookup site so we dump every three days or so as it is not big deal to open couple of handles at let them dump.

 

we also carried the 27 gal blue tank with us when we knew we would be without full hookups. The Black tank was never a issue but the gray and galley could get full in five days if not careful.

[LFDR3116]

We can make the black tank last 10-14 days for 2 of us still using enough water to avoid problems. The grey we can make last about 10 days if we are careful and use shower facilities offered at a campground.

[jperry29]

There a a lot of variables that are difficult to take into account to answer your question. Since you have previous experience with a known size tank and how long it lasted for the way YOU used it, just divide the number of days into the gallons and get your gallons per day. Divide that number into your 45 gallon tank and you should have a pretty good estimate of how long your tank will last.

[mrfrank]

Does the coach that you are looking at have 1 1/2 baths? Is one of the 2 toilets an electric flusher with grinder? The electric flusher uses a lot more water to do its job, which will fill the black tank faster, especially if someone uses the electric (rear) toilet a lot. We basically get 4 days out of a 45 gallon black tank. Wife has a bladder issue which causes more flushes. When dry camping we do not use the rear toilet, which gives us several more days.

[Onthego]

We have 100 fresh and 55 Black and 55 gray. Longest we've boondocked is 15 days during the winter west of Yuma and that was before we started using bottled water for drinking. The bathroom sink is connected to the black tank too. Being very conservative. With full hookups usually dump every 9 days. That is DW, me , a dog and a cat.

 

Jeff

[ToddandHeather]

Using all the water conservation techniques mentioned previously (navy shower every other day, paper plates, bottled water for drinking, etc.), we can go 13 days (without draining any grey water onto the ground). Might be able to stretch it to 14 or 15 days, but as yet untested beyond 13.

 

Still using all the water conservation techniques listed above, but this time draining grey water onto the ground, we can go 22 days before the black tank has reached higher than desired levels of 'fullness.' At this point, our black tank then also requires much more time to 'flush out' when we fail to dump for so many days. Also, the fresh water tank is so close to true empty, the pump starts to act a bit goofy.

[dartmouth01]

I have done the tank levelling procedure as detailed by the Wynns (http://www.gonewiththewynns.com/combine-rv-black-grey-tank) and it has worked great. Since the grey tank will almost always outfill the black, doing this allows you to use the empty space in your black tank.

[Ski]

Thanks for the responses. From what I have read, looks like a max of 14 days or so. The coach only has one bathroom and we are conservative in our usage.

 

Al

Kulpmont, PA

[TXiceman]

We have 100 gallon fresh, 70 gallon gray and 50 gallons black capacity.

 

There is no magic formula for how long the waste tanks go before hitting full.

 

TYPICALLY we can go 4 to 7 days on gray, depending on showers and if we do laundry or use the dishwasher. We will do the dishes by hand in a small dish pan and pour the water in the toilet to extend our gray water time.

 

TYPICALLY we can go 10 to 14 days on black water.

 

Ken

[2gypsies]

I have done the tank levelling procedure as detailed by the Wynns (http://www.gonewiththewynns.com/combine-rv-black-grey-tank) and it has worked great. Since the grey tank will almost always outfill the black, doing this allows you to use the empty space in your black tank.

 

I sure wouldn't want to combine the black and grey tanks!! What if you filled too high and it backed up into the shower? Emptying the grey which has a smaller outlet could pose problems with toilet paper. Just the thought of black water being so close to the kitchen plumbing. Uck!!

[travelinbob]

We have 100/75/50 and can go a week before we dump leading a regular lifestyle and not trying to save. That is not counting on my DW doing the laundry. Our 75 gal gray tank is almost full when she does 2 loads. That's right, the top load washer uses 32 gallons of water per load. If you're considering one go with a front load, they use much less water.

[hdrider]

We have 90 fresh, 66 grey and 50 black and the longest we have gone boondocking is 17 days (we also carry about 12 gallons of fresh in containers for coffee & drinking) and could have gone a day or 2 more. We have done 15 days a couple times.

[EagleEye]

We go 7 - 8 days without trying too hard. It's the gray tank that usually fills first especially we someone takes a long shower.

Usually I just make it a habit to dump every Monday.

[budeneighe]

 

I sure wouldn't want to combine the black and grey tanks!! What if you filled too high and it backed up into the shower? Emptying the grey which has a smaller outlet could pose problems with toilet paper. Just the thought of black water being so close to the kitchen plumbing. Uck!!

My first few motohomes in the 70s were just all in one tank. I got a Monomatic so I could extend boondocking . Gave me up to 5 days before I had to dump it and it only took up 5 gals in the holding tank. Then another days. Back then, grey water was not so much of a problem, though.

[Smitty77_7]

As mentioned, lots of variables. Some posters have just responded with how long they can go, but without mentioned tank sizes, it really makes it hard to relate to someone else rig:)!

 

When we shopped for our retirement traveling coach, large Grey/Black was a strong 'want' on our shopping list. We'd been in our T28 Bounder for several years, and it had 45/45 on wastes tanks. In that mode, the Grey was usually the defining tank. So much so, that I estimated we could be needing to dump the Grey, with still almost 1/2 black tank remaining. I added a pump to move Grey to Black, to take advantage of this extra 20 or so gallons.

 

I had wanted minimum 60/60 on our retirement coach. But as luck would have it, the rig that had the BIG GALLEY my wife determined was the galley we would have in our retirement coach, only had 45 Black.

 

We can control Grey, more then Black. Well, with Black we do 'Let it mellow, if yellow!' if we know we have a long stretch of boon docking.

 

Our Fresh is 100 Gallon, which usually does us quite well. But, until this years big trip, we've always use bottle water for drinking and coffee. We were no using filtered water from the main tank. So that is consuming about 2 1/2 Gallons of fresh every two days. We've agreed, and actually doing it now, that if we expect too boondock (Or say power only.) for more then 5-6 days, that we'd pick up bottled water.

 

On Grey, we stretch that tank out by washing and rinsing dishes in a pan, and then hike that outside to water the bushes. (We use common sense on this, if the item being washed has anything at all we feel is a risk to dump - we put that in the Grey tank. But with good planning, this is an exception.)

 

We also have a collapsible water bottle, somewhere around 3 gallons. (Less the 5, and more then 2 1/2...) When we run into town for anything, we will top off that bag, and then add it to the coaches tank when we get back.

 

One other thing knew to us, as of only a month ago, is we 'Sh_t Canned!' the Thetford Aria I electric toilet. Replaced with a manual flush Theford Aria. This allows us to really control what is used for flushing. At times, on extreme boon docking times, we'll flush with dishwashing grey.

 

We really don't stress out too much on this. As we are seldom less then a half hour ride to a place to get water and or dump. So not a big deal if we need to go do so.

 

My best to all, have fun, be safe,

Smitty

[Ski]

Thank you Smitty for your informative reply.

 

Al

[Kirk W]

Whether we debate the length of stay permitted by fresh water tanks or waste tanks, it will vary quite widely depending upon the habits of those in the RV. When we had our first motorhome, (7th rv) we were doing a lot of square dance weekends and our RV had 50 gallons of fresh water, and 35 gallon tanks for black & gray. At that time we were very good at minimizing water use and even with generous flush water for the black tank, we were able to stay for 3 days and 4 nights in a parking lot, with showers every day. Showers were in the submarine style with water on to get wet, off to soap, on to rinse off, and perhaps a bit extra for more needy body areas. We took advantage of restroom facilities in the hall where the dancing was as much as possible and we used disposable dishes to eat from, minimizing use of dish washing water.

 

We had friends in a fifth wheel who traveled with us and they had problems getting by for that same period with 100 gallons of fresh water and 70 gallon gray and 50 gallon black tanks. Of course, they thought also that you have to keep water running while brushing your teeth and who knows what their shower habits were, other than generous. The point is that there are many things which can be done to extend the time of use of RV resources. Washing dishes in a pan rather than the sink, then using that water to flush the toilet helps conserve all three resources. Back when we traveled with a pop-up with a very small water tank, we not only did that with dish water but we used sponge bathing most of the time and that water also was used as flush water. Doing those things not only conserves water but it also means less into the gray tank.

[budeneighe]

If you want to become skilled at boondock water management, go backpacking a few times. It really teaches you how to NOT use water you don't have to.

[pugsly]

We are usually moving every couple of days so it doesn't really become an issue. Easily 10 days-2 weeks on the black tank. The grey fills up quicker, but is easier to dump so it all balances out pretty well for us.

 

Our bathroom sink, along with the toilet, drops into the black tank. Kitchen sink and shower go to the grey. It's worked pretty well in that configuration, since the sink adds a little extra liquid to the black tank.