How often and how to clean black tank

[rvshrinker]

We have sani flushed the tank only once in 3 years. Recently I read I should be doing this more often. On the other hand some places say not to empty black too often because then there is an inadequate amount to drive biodecomposition. It does smell now despite minimal use so I'm planning to flush.

Also I read to 1. Empty tanks. 2. Fill with some toilet flushes. 3. Add some bleach and dish soap. 4. Let sit. 5. Empty. 6. Leave black tank open. 7. Flush for a while (how long?). 8. Close up. 9. Flush some water into toilet.

We use the rv for 3-6 4-16 day trips per year. And occasionally at home as a spare bedroom or office. In The latter cases, if it makes sense to avoid using the toilet we could easily do this.

[Atlee]

I laughed and grimaced at that image. 🙂 :E

Lynnmor wrote:
A clear elbow at the drain connection will tell you all that you need to know. Drain and flush often till the brown trout are no longer swimming downstream.

[way2roll]

K3WE wrote:

Lwiddis wrote:
“then there is an inadequate amount to drive biodecomposition.”

RVs have holding tanks. While breaking up “chunks” for easy dumping is a good thing RV tanks are not made for decomposing.

I have always wondered, are there signs in there that tell the ever-present microbes to NOT do what they normally do?

It's not in there long enough to decompose - at least it shouldn't be in there that long. It's a holding tank not a septic tank. Sure the microbes exist - unless you add bleach.

[K3WE]

Lwiddis wrote:
“then there is an inadequate amount to drive biodecomposition.”

RVs have holding tanks. While breaking up “chunks” for easy dumping is a good thing RV tanks are not made for decomposing.

I have always wondered, are there signs in there that tell the ever-present microbes to NOT do what they normally do?

[kellem]

I understand the craftiness and convenience this may have provided but also a significant decrease in water pressure when flushing the black tank.

But some flush is better than no flush.

[pigman1]

way2roll wrote:

austinjenna wrote:

spoon059 wrote:

If I have a full hookup site I will hook up my black tank flush and flush for a couple minutes every trip. If I am at the dump station and there isn't a backup, I will flush for a couple minutes as well. I'm probably doing it excessively, but its worked for me.

I usually keep the black tank flush on while dumping the black tank to help move along the solids, then I'll close the black tank for 2 or 3 minutes to build up the water level in the tank, then open the black tank again. That "surge" of water coming out helps to clean up most of the solids. Then I make sure to leave a couple gallons in the tank after I close the black valve again.

X3 - same process I use.

I do the same thing as you. If there is a line at the dump station I will just dump then flush back at my storage lot.

Yep, that's the procedure. Works all the time, every time.

I know the following is going to blow some of the "rules" folks minds, but... We do a lot of traveling and boondocking. I've plumbed the black tank rinse system directly into the coach's fresh water system, on the pressure side of the pump. We have two shutoff valves in that connecting line, and the system back flow preventer. This gives me a few things I ordinarily would not have. I don't need a separate black tank flush hose, I don't have to deal with a black tank hose at the flush site that someone has shoved up his sewer hose to "clean it out" and, if necessary I have a garden hose connection in that line that I can use to clean sections of the outside of the coach if I've been in VERY dirty or muddy conditions. Like the Top of the World Highway in Alaska or other unpaved places. Of course we have to be careful with fresh water tank levels, but for us this procedure has been working for over 110,000 miles in the 2013 Bus and for over 50,000 miles in the former 2008 Bus. Against the "plumbing rules"?? Of course, But it works and I'm not risking anyone but me.

[way2roll]

austinjenna wrote:

spoon059 wrote:

If I have a full hookup site I will hook up my black tank flush and flush for a couple minutes every trip. If I am at the dump station and there isn't a backup, I will flush for a couple minutes as well. I'm probably doing it excessively, but its worked for me.

I usually keep the black tank flush on while dumping the black tank to help move along the solids, then I'll close the black tank for 2 or 3 minutes to build up the water level in the tank, then open the black tank again. That "surge" of water coming out helps to clean up most of the solids. Then I make sure to leave a couple gallons in the tank after I close the black valve again.

I do the same thing as you. If there is a line at the dump station I will just dump then flush back at my storage lot.

X3 - same process I use.

[austinjenna]

spoon059 wrote:

If I have a full hookup site I will hook up my black tank flush and flush for a couple minutes every trip. If I am at the dump station and there isn't a backup, I will flush for a couple minutes as well. I'm probably doing it excessively, but its worked for me.

I usually keep the black tank flush on while dumping the black tank to help move along the solids, then I'll close the black tank for 2 or 3 minutes to build up the water level in the tank, then open the black tank again. That "surge" of water coming out helps to clean up most of the solids. Then I make sure to leave a couple gallons in the tank after I close the black valve again.

I do the same thing as you. If there is a line at the dump station I will just dump then flush back at my storage lot.

[spoon059]

Tvov wrote:
Okay, so you DO rinse your black tank. Yes, a properly cleaned out black tank does not smell.

Yes, hence ;

spoon059 wrote:
If I have a full hookup site I will hook up my black tank flush and flush for a couple minutes every trip. If I am at the dump station and there isn't a backup, I will flush for a couple minutes as well. I'm probably doing it excessively, but its worked for me.

I usually keep the black tank flush on while dumping the black tank to help move along the solids, then I'll close the black tank for 2 or 3 minutes to build up the water level in the tank, then open the black tank again. That "surge" of water coming out helps to clean up most of the solids. Then I make sure to leave a couple gallons in the tank after I close the black valve again.

Sanitizing your poop tank is wasting money and resources. That was my point. Hope to see you out there some time!

[frankwp]

rvshrinker wrote:
3. Add some bleach

That is generally a bad idea. If the dump station or campground uses a septic system, the bleach will mess up the decomposition process.

As mentioned, a clear elbow is essential to the process because you need to know the state of what's coming out of the tank. We always camp with full hookups & only rarely use dump stations.

This is my routine:
- When the tank needs dumping, I turn on the sani-flush for about 30 seconds to "stir the soup", then open the dump valve. The sani-flush stays on for the duration of the dump.
- When the water is coming out clear, the dump valve is closed. The sani-flush then serves to put water back in the empty tank. I have one of those garden hose water meters & it lets me know when I have about 5 gallons in the tank.
- When breaking camp, I do the dump, but I'll put about 15 - 20 gallons back in, then dump again. Then I'll fill the tank with about 20 gallons and 1-1/2 cups of HE (low suds) laundry detergent. That mix stays in there until I get to a dump station that is close to home and completely drain it, put in 5 - 10 gallons, and completely drain it if it's the end of the season. If not, 5 gallons goes back in.

It's amazing how much gunk gets cleaned out by the detergent and the agitation of driving down the road for a couple of hours. I also give the galley tank the same treatment at the end of each system. I don't use any other tank chemicals.

The final dump of the season takes 10 - 15 minutes, so I do it at a dump station close to home where it costs me $10 to dump & I don't have to feel bad about taking my time.

[Tvov]

spoon059 wrote:

Tvov wrote:
I don't think it is just my camper or my diet... many friends with campers have said that if their tanks aren't thoroughly rinsed, their campers will smell after sitting in storage or just sitting unused for extended periods.

Try dumping your black tank, but don't rinse it or use toilet chemicals afterwards. Let your camper sit unused for months.

I would be impressed and surprised if your camper doesn't end up getting that "black tank smell". May not be over whelming, but it is there.

If you can store your camper without rinsing the black tank, and have no smells after an extended period, keep doing whatever it is you are doing!

It is possible we are thinking of the same thing, but using different terminology.

For 10 years I've rinsed and left water in the bowl, never had any sewer smells in my camper. One year my wife was pregnant and very sick, we didn't camp at all that summer. No special arrangements made and zero sewer smell in my camper. Clean it properly and maintain it properly and it will not smell. Fail to either clean it or maintain it and it will smell. You can fill the tank full of bleach to mitigate other problems, but it won't solve those other problems.

If you have to sanitize your black tank (literally, clean it to make it sanitary, thus no traces of human waste) to prevent smell then you have something else going on. The systems are designed to hold human waste and not smell inside the camper. If your camper is leaking sewer odors into your camper, it is potentially dangerous and clearly not working as designed. You should look at getting that fixed, rather than masking it with sanitizers.

Okay, so you DO rinse your black tank. Yes, a properly cleaned out black tank does not smell.

I go an extra step and sanitize the tank when we aren't going to be using it for an extended time.

As far as I am aware, our camper and its tanks are fine and in proper working order, same as my friends that have similar issues when they don't clean out their black tank.

We are just talking in circles now - so keep taking care of your camper the way that works for you, I will take care of mine the way that works for me.

Maybe we'll meet at a campground somewhere!

[Guy_Roan]

As far as I am concerned if you use chemicals in accordance with their instructions and after every time you dump the tank rinse it with about ten gallons of water, you should never have to clean it.
In twenty years and three different trailers we have followed that criteria and never have had a problem.
We, (my wife and I) have snow birded for the last ten years and I follow the above criteria and dump the tank every seven days.
Also, for what it is worth, we use regular supermarket toilet paper

Guy

[spoon059]

Tvov wrote:
I don't think it is just my camper or my diet... many friends with campers have said that if their tanks aren't thoroughly rinsed, their campers will smell after sitting in storage or just sitting unused for extended periods.

Try dumping your black tank, but don't rinse it or use toilet chemicals afterwards. Let your camper sit unused for months.

I would be impressed and surprised if your camper doesn't end up getting that "black tank smell". May not be over whelming, but it is there.

If you can store your camper without rinsing the black tank, and have no smells after an extended period, keep doing whatever it is you are doing!

It is possible we are thinking of the same thing, but using different terminology.

For 10 years I've rinsed and left water in the bowl, never had any sewer smells in my camper. One year my wife was pregnant and very sick, we didn't camp at all that summer. No special arrangements made and zero sewer smell in my camper. Clean it properly and maintain it properly and it will not smell. Fail to either clean it or maintain it and it will smell. You can fill the tank full of bleach to mitigate other problems, but it won't solve those other problems.

If you have to sanitize your black tank (literally, clean it to make it sanitary, thus no traces of human waste) to prevent smell then you have something else going on. The systems are designed to hold human waste and not smell inside the camper. If your camper is leaking sewer odors into your camper, it is potentially dangerous and clearly not working as designed. You should look at getting that fixed, rather than masking it with sanitizers.

[Tvov]

spoon059 wrote:

Tvov wrote:
If the black tank isn't thoroughly rinsed out and sanitized it will stink up the camper.

Either you need to inspect your diet or your camper. Your toilet has a water seal that prevents smells from coming back inside. Your tank has a vent tube that prevents gases from trying to find another avenue of escape. If you are getting smells, you've got problems. A properly working RV black tank system shouldn't smell. 10 years of camping, the only black tank smells are when someone forgets to turn off the Hengs vent fan while flushing. The fan creates enough pull to pull tank odors when the toilet drain is open.

I don't think it is just my camper or my diet... many friends with campers have said that if their tanks aren't thoroughly rinsed, their campers will smell after sitting in storage or just sitting unused for extended periods.

Try dumping your black tank, but don't rinse it or use toilet chemicals afterwards. Let your camper sit unused for months.

I would be impressed and surprised if your camper doesn't end up getting that "black tank smell". May not be over whelming, but it is there.

If you can store your camper without rinsing the black tank, and have no smells after an extended period, keep doing whatever it is you are doing!

It is possible we are thinking of the same thing, but using different terminology.

[magicbus]

spoon059 wrote:

Tvov wrote:
If the black tank isn't thoroughly rinsed out and sanitized it will stink up the camper.

Either you need to inspect your diet or your camper. Your toilet has a water seal that prevents smells from coming back inside. Your tank has a vent tube that prevents gases from trying to find another avenue of escape. If you are getting smells, you've got problems. A properly working RV black tank system shouldn't smell.

X2.

Dave