How long can black water tank go until dumping?

I'm new to this "black water" thing and have been doing a lot of reading on this forum to make sure I do it right.  Lots of good info.  The consensus seems to be LOTS of water to break down the contents.  I want to get to that 3/4 full mark without having to add water through the toilet,  But how long can I go between dumps?  A few days, a week, a month?  I figured my nose would probably be a good gauge, but I want to know what the RV community has to say.

Any preferred additives.  Saw a read on "RV Boss" with some raves.  Anything out there that will be OK in a home septic system?  I may have to pop the lid on the tank at home, and dump a load at times

It depends on the size of the holding tank as well as flushing procedures.  Our 40 gallon tank can go for up to 10 days between dumps with 2 of us, and 2 weeks if I'm alone.  We don't use an excessive amount of water and have never had any problems with the tank in over 16 years of full time usage.

I keep my RV at a semi permanent site during the summer so the black water and the gray water doesn't  get drained  until they close to 3/4 full.  At that point I use a blue boy to drain the tanks or I'll hook up and go someplace to drain them.
How long depends upon the usage. A weekend with several of people can fill the tanks, especially the gray water , with shower and dishes. 

Cracking open your septic tank to dump will take your breath away.

Do you have a clean out between the house and tank that you could use? 

There are pumps that you can use that pump the sewage through a water hose. There is also
a kit the uses the water flow of a hose to drain the tank.

As far and additives, the only thing I use is "septic safe" toilet paper. 

As for cleaning, check your manual and I'll bet there is a method the your RV manufacturer recommends.

Remember, to keep the dreaded pyramid away, you need to flush with lots of water.  Don't try to go for a long time by using only a small amount of water, or you could end up with problems. 

Depending on many things Wife and I hit 8 days once on a 36 gallon tank, We used a lot of other toilets though (park/Truck Stop)

Since her passing.. I hit 2 weeks.

Sometimes smell will determine when its time

The problem is the paper, not the "Poo". The absolute least amount of paper, even ones which come apart easily, plus enough water and a dose of chemicals every day or so and it will come out in a nice whoosh!  We have gone two weeks many times over several summers in Alaska and no problems ever.

Not till it gets above the rim of the toilet....I empty mine as a single person about once every two weeks or so - I use plenty of water and watch through the toilet until I see water rising to near the bottom of the toilet...then dump - when traveling I usually dump every 4 or 5 days...don't want it sloshing around too much when on the road....

You will know, every tank is a little different, but make sure you use plenty of water....after emptying I put about 5 gallons of water in the tank so the solids are landing in water which helps the start of breakdown.....you don't want the waste landing in a dry tank - you will end up with the dreaded poop pyramid....then you will have problems....

Good Luck,

Jim

Had a situation back in '96 where we had the MH in the driveway to take to the dump, about 3/4 full.  I got sick and it did not get dumped for almost 9 months.  No problems as everything was quite liquid by the time we did the deed. 

Thanks Jim, that's what I was looking for.  I'm a weekend warrior, and it may be as long as two months between camping trips.  Probably won't stay out but a night or two.  I wondered if I could let the tank go for a few weeks or even a few months, until it fills, without having any problems.  I just don't think I'll be filling a tank over a weekend.  I'll certainly not let it sit for a season, and I'll check it periodically to make sure plenty of water is in the tank.  I plan on performing a good cleaning each time I dump it, especially during winterization.  Picked up a Rhino Flex hose kit and a Camco RV Dual Flush Pro to backflush and clean the tank.

We usually go about two weeks (full time) between dumps for the two of us. Plenty of water and 2/3 full minimum before dumping. We never use any treatment in the tank; just make sure the pile is below the surface of the water (it levels naturally).

Ernie

We - my wife and I - have a 35 gallon tank and can go 10 to 12 days before we dump.

In my experience, the toilet seems to smell more when the liquid level is lower.  Maybe the airspace allows more smells to accumulate?

I know opinions vary on this topic, but we don't use any chemicals.

A lot depends on the temperature.  The black tank turns ripe a lot sooner in hot weather than when it's cooler.  After I dump my black tank I add enough water to fill the outlet pipe and cover the tank floor below the toilet, then I use the toilet normally.  In the summer I can go a week or so before my nose tells me it's time to get rid of the contents, in cooler weather that same point isn't reached for a couple of weeks.

But don't pop the top on the septic tank and dump the RV directly into the septic tank.  Your tank has internal baffles to make sure the incoming effluent stays in the tank long enough for the algae to digest the waste and nothing but clear water goes into your leach field.  Dumping through the clean out lid stirs up the tank contents and sends raw effluent out to your leach field until everything settles down again, which will shorten it's life.

There should be a cleanout plug somewhere between your house toilet and the septic tank.  Dump your rig into it instead, so the baffles inside the tank can continue doing their job.  If the cleanout is underneath the house, get some pipe and extend it to where you can reach it with the sewer hose.  Or have a plumber install a cleanout port in the drain line between the house and septic tank.

And don't use any RV tank chemicals if you're going to dump into your septic.  They'll kill the biological action that breaks down the waste in your septic tank just as effectively as they do in the RV's holding tank.

I'm pretty sure my cleanout is under the house.  I'll have to add "put in another cleanout" on my project list. Until then, guess I'll add water to black water tank and dump it before I leave a site.