How often to dump black water tank

[plmulhern]

I am a new owner. Just made a long delivery trip. Not much in black tank and nothing in grey water tank. It is still winterized.

Should I wait until I have half a tank or so to dump? Or does it really matter.

I've had boats all my life and never worried about emptying the tanks until they were full. Is this any different?

I am in Houston so in a couple of weeks I am going to clear out all the antifreeze. We've probably had our last freeze but I will wait to make sure.

[Bluto]

If your not going to use the trailer for a week or so I would fill the black tank with fresh water and then dump a full tank. If you dump a partial tank it will have the tendancy to clog the dump valve. Then rinse the tank and your all set.
A clogged or partially clogged valve is something you'll want to avoid at all costs.
I would just run a hose thru the trailer to the toilet to fill the black water tank. Then dump when full.

[PaulnGina]

Regardless of how much is in the black tank, I would suggest that you dump it at the end of each trip and as often as you can while travelling. Same for the grey tank, for that matter. I just don't like leaving anything in them any longer than I have to.

[polarlyse]

I agree with all the above. We've gone 4-5 days without dumping either because we're dry camping or there's a long line at the dump station and I wanted to move on. I always plan to arrive home with empty tanks. Even the fresh water. That is unless we're going out again in a few days. I sometimes put some bleach into the fresh tank and let it slosh around and dump it when I get home. That way it's ready for the next trip. Now the grey tank is another matter. If you follow serious water conserving usage we've gone 4 days easily. This is usually the more limiting issue so plan accordingly.

[AldeanFan]

Yep, good advice sofar.

My rule is to dump at the end of every trip, and as infrequently as possible during the trip.

Don't let the trailer sit with anything in the tank as things will settle to the bottom and cause backups and other nasty problems.

When you do dump, you want a mostly full tank so there's lots of liquid to flush things out, it it runs slow, solids will backup in the hose and the drain pipes. I always top the black and grey tanks off with fresh water before I dump.

Last trip of the season before i winterize we dump before leaving the campground, then add a bag of ice and a bucket of water to the black tank and a bucket of water to the grey tank. As we drive home it sloshes around and knocks anything accumulated in the tank loose. Then we stop at the city yard, top off the black and grey tanks with water and dump.

[Msmoto]

Both the gray and black tanks contain human waste from shower and toilet. Thus, with my desire to keep the oder down, and I will flush my tanks at the end of each trip, usually within an hour of coming home. I do have the convenience of a garage with dump site where the AS is parked, so it is convenient. The worst problem might be to have solids settle on the bottom of the black tank, and not be so easy to dislodge when flushing. I flush my black tank with water until the effluent is clear. My gray water tank is drained and then a small amount of water is restored so as to prevent a drying out of the valve seal.

Also, the black tank is given about five gallons of water and my deodorizer fluid is added.

About a half cup of deodorizer is added to each drain, shower, sinks, etc. and two cups to the black tank via the toilet, then some water run down each drain. This keeps things much more fresh than if waste is allowed to remain in the waste water pipes.

FYI, this is what I use for my holding tanks:

Mix in one gallon jug

Holding Tank Deodorizer

1 CUP Purex 2

1/2 CUP Pinesol

3 TBLS household ammonia

Mix in one gallon jug, add half gallon hot water, swish around and add hot water to fill.

Place two cups in holding tank after dumping and filling with a few gallons of water. Makes 8 treatments for 55 gallon tank.

I also will occassionally dump kitchen cooking grease into the toilet so as to lubricate the seals.

[russ240]

Please note that this was posted in the Interstate forum and they have macerators so the replies from trailer users which don't may not be exactly what an AI owner wants to do. Personally, since I consistently use my AI around town a couple of times a week (largely because I like having my own private toilet) dumping "after every trip" would be preposterous. I dump about once a month whether I need to or not or any time I get up to past 2/3rds full. Before dumping I add water on top and drive around a bit if I'm concerned that there is not much in there or it is mostly solids.

[Drathaar]

Originally Posted by Msmoto

Both the gray and black tanks contain human waste from shower and toilet. Thus, with my desire to keep the oder down, and I will flush my tanks at the end of each trip, usually within an hour of coming home. I do have the convenience of a garage with dump site where the AS is parked, so it is convenient. The worst problem might be to have solids settle on the bottom of the black tank, and not be so easy to dislodge when flushing. I flush my black tank with water until the effluent is clear. My gray water tank is drained and then a small amount of water is restored so as to prevent a drying out of the valve seal.

Also, the black tank is given about five gallons of water and my deodorizer fluid is added.

About a half cup of deodorizer is added to each drain, shower, sinks, etc. and two cups to the black tank via the toilet, then some water run down each drain. This keeps things much more fresh than if waste is allowed to remain in the waste water pipes.

FYI, this is what I use for my holding tanks:

Mix in one gallon jug

Holding Tank Deodorizer

1 CUP Purex 2

1/2 CUP Pinesol

3 TBLS household ammonia

Mix in one gallon jug, add half gallon hot water, swish around and add hot water to fill.

Place two cups in holding tank after dumping and filling with a few gallons of water. Makes 8 treatments for 55 gallon tank.

I also will occassionally dump kitchen cooking grease into the toilet so as to lubricate the seals.

There's some possible dangerous chemistry in the list of ingredients.


Why You Shouldn't Mix Bleach and Ammonia

[ROBERTSUNRUS]

Originally Posted by Drathaar

There's some possible dangerous chemistry in the list of ingredients.


Why You Shouldn't Mix Bleach and Ammonia

Hi, yes; I was wondering about that too.

[ROBERTSUNRUS]

Hi, we try to dump the black tank when full, or once a week. In over ten years, my black tank has never been full except when we fill it to the top, then drain it. More than a week, in hot weather, or without adding more chemicals will start to stink. We don't like stink.

[mandolindave]

Is whether to use enzymes or chemicals as a tank treatment. ( Hint,,,,I use enzymes )

[iowaroots]

Keeping those tanks clean as everyone says is important. The tank sensors that show how full/empty they are can become a problem if not kept clean. In addition I would think you have a black tank flush system builtin where you attach a water hose to it outside in one of the compartments and use that to not only load fresh water in it and it also stirs it up which once reasonably filled will prove to be a better flush of the system. Doing it twice is a good idea if storing it for a while. In addition you may want to fill with extra water and drive around to help loosen anything that may have settled.

[koosdhr]

I learned from some experienced Airstreamers that the stuff in the black tank needs to sit and work for a few days in order to come out easily. So dumping every day or every other day is too often. Of course there is always some that has gone in recently, but as long as the majority is more than a day old, most of the solids will have become soft and your tank will become clean much more easily.

Right after dumping, we flush the tank with fresh water (there is a special connector on our dump tube for this) so that the tank and the sensors are clean again.

Of course, if you have a macerator, things are a bit different. Then you do not need to wait for the solids to get processed and you can dump more often.

[thehandyman]

If your eyes start to burn and water when entering you waited to long.

[PaulnGina]

Originally Posted by russ240

Please note that this was posted in the Interstate forum and they have macerators so the replies from trailer users which don't may not be exactly what an AI owner wants to do. Personally, since I consistently use my AI around town a couple of times a week (largely because I like having my own private toilet) dumping "after every trip" would be preposterous. I dump about once a month whether I need to or not or any time I get up to past 2/3rds full. Before dumping I add water on top and drive around a bit if I'm concerned that there is not much in there or it is mostly solids.

Macerator or not.......

I would guess that most folks would interpret "trip" as a camping/road trip, not just running errands.

[graysailor]

I have had boats also but Rv's are a little different. In hot climates I only go about 3 days. When its colder you can go a little longer. When I will not be using the trailer then I dump the tanks and refill the black tank and dump again. On my boats I never really had an odor problem but in an RV you will if you do not dump on a regular basis. BTW to save some loot I make my own black tank additive. In an empty gallon container put in 1 small bottle of (I think a pint) of Pine Sol, a few scoops of boraxo and fill with water. I just add a cup of this solution to the black tank after dumping.

[gecko]

All good advice! But on thing I don't see mentioned here is weight.

The difference between the unladen and max weights on our Airstreams seems like a lot--but it's really not. Your clothing and beauty supplies for two people probably weigh around 150-200 lbs if you're going on a long trip and packing two weeks of clothing and then doing washes on the way. (We know this from weighing our bags when we fly to destinations.) Dishes, utensils and a full set of pots and pans can vary, but are probably another 100+ lbs. Do you carry wine? Beer? 8 lbs per gallon, so if you've stocked up for a long trip...The groceries--do you pack canned foods? Do you carry separate fresh water for drinking? We do--as much as 12 gallons (96 pounds right there.) How about your tools, chairs, BBQ and everything else in your (albeit tiny!) storage compartment? Books? Have you added more batteries for solar? Maybe bicycles off the rear? Of course, the best way to tell is to weigh your laden trailer. But a quick tabulation even without weighing will probably bring you very close to, or just over, your max weight.

And that is with zero water in any of your tanks. As I'm sure you know, water weighs 8lbs/gallon. If you fill up your fresh when you travel, that 40 gal tank holds 320 lbs! If you leave your black 1/2 filled, that's a total of 480 additional pounds between the two. And the difference between your trailer's empty weight and GVW is probably between 1000-1200 lbs!

As you may have guessed, we always travel as empty as we can. Black and grey are emptied every day if we are traveling each day, and we fill the fresh between 1/8 and 1/4max--that's between 40 and 80 lbs of water in the tanks. We do use the outside flush mechanism almost every time when we're on the road, for all the reasons stated in the other answers here.

When we are camped in a park for long periods of time, our behavior is much more like the other people here. But if we're doing a lot of driving, we want to be as light as possible and start the black and grey empty at the beginning of each day with a thorough secondary flush from the outside hose opening before we go.

By the way, love Aldean Fan's suggestion as to the ice cubes--hadn't thought of that one and will definitely use it!

[Msmoto]

I think the formula I have for a deodorant does not contain bleach, so I am wondering what the concern was. Maybe someone can inform me if I am mistaken. My idea of "bleach" is Clorox at about 5-6% sodium hypochlorite. And for sure mixing this with ammonia is not to be done.

But, let me know if I am misinformed.


Ms. Tommie Lauer
Sent from my iPhone using Airstream Forums

[J. Morgan]

According to the site I visited, Purex II has no chlorine.


1/2 Ton 4WD Truck, 72 Sovereign Hensley Arrow

[scamp]

As for the ice cubes in your black tank there is a video on you tube that proves it doesn't really work , the video shows a clear tank installed in the back of a pickup with ice cubes added to the tank and he drives around like a mad man in parking lots to mix the solids in the tank and you can see at the end of the video it doesn't really work . I will see if I can find the you tube video.
I tried it doesn't work but here is the video name( do ice cubes in a rv black tank really work) just type that in the search area
Don