I'm told you're not supposed to use bleach in your black water tank - but no one can tell me why.......


Does anyone know?


Tags: Bleach deadly for RVers in Blackwater tank, black water & Bleach deadly

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Since nobody has suggested it yet, a good alternative to calcium hyperchlorite (household bleach) is 2% hydrogen peroxide. All the info on how to manage your black water holding tank is excellent, but doesn't address your original question. I think. Peroxide doesn't react violently to what's in the tank, and is excellent for killing surface congregations of baaaad smelling bacteria. And it's cheap!


one of the reasons it is not used much is it reacts to various metals and can also react to certain organic items as well. if the tank ahs been rinded and water added then peroxide it will clean the plastic and rubber parts but will also eat away at the prod points used in most black tank sensors. it has the same effect in a freshwater system and will celan it but again any metal prods in the tank will slowly be eatened away with each use. and peroxide will oxidize any minerals in the water as well, so thats another reaction.


it also oxidizes hydrogen sulfide, mercaptans, amines and aldehydes. -
destroys residual chlorine and reduced sulfur compounds thiosulfates,
sulfites, and sulfides)  Oxidizes cyanides, NOx/SOx, nitrites,
hydrazine, carbonyl sulfide, and other reduced sulfur compounds
mentioned above.  Organic oxidation - Hydrolyzes formaldehyde, carbon
disulfide, carbohydrates, organophosphorus and nitrogen compounds, and
various water-soluble polymers; and (with catalysis) destroys phenols,
BTEX pesticides, solvents, plasticizers, chelants, and virtually any
other organic requiring treatment.  Oxidizes ferrous iron, manganese,
arsenic, and selenium.

so using such you should not have the type of tank that has probes as eventualy like bleach they will be gone. it is juts a bit safer to use than bleach but can effects not wanted   redwing


I think that you might be going a little overboard here. I'm not suggesting that anyone pour gallons of peroxide into a holding tank, we're talking about spraying a small amount from a spray bottle onto the flush valve mechanism to clean and kill bacterium that aren't down in the tank where they belong.

basically what you are saying is you can clean the bowl with a few sprays of a bottle....why would it be dirty if you used it properly, i have 20 years on one and it is as white as the day it was made. and i can clean mine if it ever needed cleaning with just dropping a tablespoon of ridex in the bowl add some water wait ten minutes and flush and the ridex will go down into the tank and clean that as well. your suggesting in your first post it was for cleaning the tank as the question was put out.

Sorry about that - I was replying to Richard Cobbs question on how to clean his waste valve, not the tank.

As far as why valve parts get dirty, many people don't always take the time to completely clean the inside of their toilet prior to putting a rig up for the Winter. My Hall GTC happens to have a spray valve mounted next to the toilet for the express purpose of washing the bowl down - looks like an old "Dishmaster"  - which works extremely well.

Thanks for the reply.  I gave up on the water valve long ago (1977 toilet) and only use a high pressure spray wash down (less water and breaks up toilet paper).  Still, being a single male, I don't clean as often as I should.  I will try to locate Rid-x down here.  In the interim, I will disassemble  and try hydrogen peroxide to clean and then flush the parts with water prior to reassembly.  As far as odor is concerned, my experience is that the only odor that I get (unless the the tank is so full that I block the vent) is from my poor cleaning of the bowl.  I have added two pick-up caps on top of my camper to provide a loft bedroom and excellent ventilation.  I am able to raise and lower these with four scissors jacks that I power with motors that I got from an old hospital bed.  My plumbing vents extend about 15" above the original top; when the two pick-up caps are raised up, then the outside (larger) vent pipe extends 30" up.  I think that this high pipe and possibly double vent setup draws the odor so well that it never enters the RV.  I do not use any deodorant or any thing else in the toilet/tank. 


p.s. Hard to explain, check out my page and pictures.  Built for Central America.

one thing to realize is if you do add water to the bowl before using it for number 2, you won't need the spray as often and if you do not very much, with water in the bowl it makes it slick and nothing will stick to it, there usually is a picture of how to flush the toilet on the lid if not, just fill it 3/4 of the way which is about a 1/2 gallon of water, and your bowl should be clean when you flush it into the tank.   and maybe you haven't heard but single ply toilet paper won't clog up the system as well, a cheap alternatice to rv toilet paper is scott tissue, you get a 1000 sheets instead of the 125-250 most double ply gives you per roll, scott is also safe for septic systems and since your tank is about as close to a septic system you can get to, it makes sense to use it. if you ever get a lady in the house for extended periods and full time camp alot, you may have to explain about the mexican way of toilet paper use, that method is all number 1 paper gets put into a waste basket and again save you from the dreaded plugged waste valve. you really don't want to know how to bust that plug up.   


in the url below at the bottom of the page is an owners manual for a thetford, it shows how to add water but most importantly about not using checmicals in the bowl because of damage. of course yours has a hand spray only it can work just as well as the hand flush fill or the foot flush fill, but using the toilet properly you won't have to worry about stains and other problems and it will make you a happy camper.   redwing


installation and owners manual:


Hi Robert,

  Great informative responses from all the great folks at Good Old RV's. I hope all this information helps you and others who read them. I would just like to add a couple of more suggestions as long as we are talking about holding tanks. As a RV Tech at Poulsbo RV I learned that Baking Soda has many benefits, if you are experiencing false readings from your holding tank gauge you simply fill the tank with water and a substantial amount of Baking Soda (depending on the size of your tank) let it soak for a while and  it will clean the contacts that emit the signal to your Monitor. Cleaning your tank out with Baking Soda before your park your RV for a while also helps keep it clean and odor free before you use it again (this was a must for RV's that sat on our sales lot for a while). We also took in a lot of RV's on trade that had holding tanks with strong odors and we used Baking Soda to deodorize them. Grey water tanks can stink too so don't forget them, water from P-traps can evaporate over time (especially in some of the hotter States) if your RV is parked unused for a while and can let the odors from these tanks escape into your RV. As a foot note I would like to mention an old RVing aid in loosening solids stuck in your black water tank, right before taking to the road add a bag of crushed ice or two or several ice cubes into your black water tank, the motion will slosh the cubes around and should loosen those stubborn stuck solids. The ice will eventually melt mixing with the loosened solids making it easier to dump but I would recommend adding some water to aid flushing out your tank at dump time. Baking Soda and Ice are cheap easy ways to maintain your holding tanks.  Happy camping everyone! 

Les, I have not read of this baking soda solution. It sounds like an excellent solution. I assume we have to be careful that no other chemicals are in or put into the tank so no hazardous gasses are released? Not sure about that, but used alone it sounds "refreshing".   Also, do not tell anyone about Poulsbo and all the fantastic dry camping around you... :)

Hi Pat,

   You are absolutely right about mixing chemicals! I should have mentioned we only serviced holding tanks after they were dumped and rinsed. I should have also mentioned that I am a full-timer and live in a nice 16 space RV park with great neighbors who have benefited from using baking soda in there RV's and other useful suggestions from me.  

Hey, sounds like you've got the right spot! I really like this simple and inexpensive baking soda idea. Hope folks use it too. Keep those ideas coming.  pat




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