How Do I Sanitize My Black Water Holding Tank?

[MIGUY]

Anyone have a process on how to sanitize the black water holding tank?

 

[Orick]

Welcome to the forum!  There's been more discussion on this topic than most others and you can use our search function to find many threads and methods to choose from.  Here's one on the popular "Geo Method".  http://www.rvforum.net/SMF_forum/index.php?topic=43071.msg397927#msg397927


good luck

Rick

 

[MIGUY]

I remember once reading about a process that only had me use baking soda? or Vinegar? I had to fill the tank of course. I just can't remember the process totally and I can't find anything like it online anymore. It did work very well.

 

[Tony_Alberta]

What do you mean by sanitize?  If just to clean it up of every day "stuff" why bother?  After all you don't sanitize the sewer lines in your house.

If you are having a specific problem or some sort then sure.  If so what is the problem?

 

[Gary RV_Wizard]

There is no need to "sanitize" a black tank and in fact the job would be nearly impossible to achieve. Why sanitize something that is going to get incredibly contaminated on the very first use anyway?

Just drain and rinse the tank if you expect to store it for awhile. Otherwise, just use it and flush occasionally to remove accumulated crud from the walls of the tank. An occasional  (once ort twice a year) dose of a septic tank enzyme product like Roebic 57 or Rid_X can help keep it free of gunk.

 

[MIGUY]

It just smells incredibly bad even after I empty and spray it. I am worried the vent might be plugged? I just thought there had to be a cleaning process to give it a good wash out.

 

[ZuniJayne]

It is possible that a vent might be plugged, or installed too far down into the tank.  Check it out first with a flashlight.  You many need to insert a long, sturdy stick or rod to knock a blockage back into the tank. If one is there, let it soak well in hot water in the tank for a while before opening the dump valve.  You don't want it to plug the dump valve or pipe.  That can get REALLY messy and frustrating.

The latter is the case with my Fox's tank, so I don't get full use of the tank capacity without it starting to smell in hot weather.  Raising the vent pipe can be a MAJOR undertaking, so I've learned to live with it and dump a little sooner.  Try to precharge your black tank with at least 10 gallons of water before use.  The more water you have, the more smell is diluted.

There may be some kind of chemical residue left in the tank from previous owners.  Rinse, for hours if necessary, using a wand that goes down into the tank and can spray the corners really well. 

NEVER, NEVER use anything with chlorine in your black tank!  It mixes with urine and makes a DEADLY gas!

 

[seilerbird]

The problem might be a poop pyramid. If the holding tank is emptied repetitively before it reaches the 3/4 full mark you can end up with a poop pyramid right below the toilet inlet. I had that problem with a class C I bought a few years ago. It always smelled.

I turned off the water, opened the flush valve and peered down into the holding tank with a flashlight. Once I saw the problem I got a garden hose with a spray attachment and kept spraying into the holding tank, via the toilet, until the poop pyramid had dissolved. I was at a dump station with the sewer hose attached. It took me about 20 minutes to completely get rid of the residue and then I kept spraying into the tank for about ten more minutes. The smell was completely gone after that.

Another reason you can end up with the poop pyramid is if you don't add enough water to the black tank after you dump. I hold the flush valve open for at least five minutes after I drain the black tank and close the external valve. I figure this puts about 10 gallons into my 30 gallon tank. When I flush I always count to five to make sure the the waste gets diluted.

 

[dcmcderm]

I have a similar question, I tried searching but couldn't find exactly what I was looking for.  We just went out for our first weekend trip (ever) last week.  What do I need to do to the black water tank just for regular maintenance?  All I did last week was empty the tank and ran a bit of water down the toilet (while the valve was open) to hopefully flush it out a bit better.  Is that good enough for day-to-day use?  We'll be heading out for lots of short trips this summer, so I want to make sure I'm doing enough cleaning every time I empty the tank.

Then obviously at the end of the summer I'll do some sort of more thorough cleaning/sanitizing, but is that sort of thing necessary more often?

 

[Jeff Brown]

Personally if I know when the next trip is scheduled and the tank is not that full I'll add a couple of gallons of water using gallon jugs down the toilet and leave it sit like that until the next usage.    we usually have hookups and go out ever 3 weeks or so and I find I have to dump grey every trip and black ever other trip.

Jeff

 

[sgtjoe]

Just a few thoughts;

It might be the gray water tank, check under each sink and look for a drain type pipe that goes up and has a valve type cap on top that may be loose or plugged.  This was the problem smell in my MH, when I found the valve it was loose and when I tightened it the smell was gone.

The other thing I did was to make sure any vents close to the tank vent pipes were closed while moving down the road.

I also replaced the vent caps on top with those thingees that rotate in the wind.  Can't recall what you call them, but I'm sure someone here will chime in with the name for it.

If you don't have a flushout fitting for your black tank you might want to install one.  If you can look down through the toilet to the bottom on your holding tank there is a wand that will attach to your bathroom fawcet and they work pretty good.

 

[ArdraF]

Anyone have a process on how to sanitize the black water holding tank?

To answer your specific question, no because we don't sanitize black tanks.  You just flush it well with enough water to get all the debris out through the hose (previous comments apply).  For black tanks, you want to retain an enzymatic action so that the waste breaks down naturally.  Sanitizing a black tank stops that natural breakdown so you don't want to do that or you'll end up with odor problems.

We DO sanitize fresh water tanks so that they don't get contaminated and we can drink the water safely.

ArdraF

 

[John From Detroit]

I second that. Why would you even want to sanatize a black tank.. IF anything I want MORE bacterical action in that tank, not less. (Bacteria eat teh soilds and help to liquify them,  I know that over a few days it won't make much difference, but I've been known to go a week between holes in the ground.)

 

[Conquest aka Robert]

If you have smells you can try RID-X in the tank it will help break down the STUFF in your tank which is where the smell comes from :. I always put some in the tank right after we get back from a trip with a couple of gallons of water.

 

[MIGUY]

Leaving it alone for more bacterial action makes sense. But from what I am reading it sounds like I should just get some RidX and fill the tank with water, drive a little bit and let it slosh around a bit to get all the corners and the the mouth of the vent where some of the "stuff" can get trapped, then dump out. What do you all think? Sound like a plan?

 

[Tony_Alberta]

Sure but why bother dumping?  Let those 3 or 4 gallons of water stay in there so things don't get too dry.

 

[Conquest aka Robert]

RID-X is not fast acting its bacteria and works slow. If you go the fill and drive route you need to let it sit for a few days before you dump to give the stuff time to work.

 

[sgtjoe]

A bag of ice down the toilet and drive around for a while, this helps clean the stuff that wants to cling to the tank.