Bleach in the Black Water Tank and a Bullseye on my Back

I have been catching some flak from a rather vocal group that firmly believes bleach should never be added to the black water waste tank on a recreational vehicle which I advocated in this post.  I still stand by this post and will try to explain my reasoning further.

To start off,  what you put in your RV wastewater tanks is your business but judging from the number of visits I get from people Googling,  many people must not be satisfied with the current state of their holding tanks.

I use bleach in 3 different ways around the RV Basecamp.

1. I use it as an algaecide in my portable 300 gallon water tank.
2. I use it to sanitize my  onboard freshwater tank and lines 2x per year.
3. I put bleach in my RV black water tank to get rid of odors.

Number 3 is the action causing all the hubbub.   People seem to believe that bleach will devastate a septic system.  Simply not true when used in moderation.  And how do I know this?   Regular readers know I refrain from writing about things I have not experienced or dealt with directly.  I detest Internet Commandos!  (An Internet Commando is a person who feels like they are an expert on any subject because they have read about it on the Internet.  ) So when I am talking about adding bleach to my wastewater tanks, I am speaking from experience.  I did it this year and years previous with no ill effects to the septic system.  I might add – septic systems I usually installed with my own 2 hands.

Lets’ get logical for a minute.   An RV wastewater tank – black or gray- is NOT a septic system.  It is a holding tank.  Here is the best description of an RV wastewater system I have ever read and it was posted on an internet forum.  Go figure

What happens in your tank when left natural is the very early stage of the same action that would happen in a septic system. Based upon a discussion with an environmental chemist & a septic system design engineer that I know, it is absolutely true that the waste is not in the tank nearly long enough to complete the process, which is the reason that you don’t want to use the effluent of that tank to water your flowers!

In the septic action, 80% of the solid matter will be fluid within 48 hours(60% in 24), but far from that amount is truly liquid but rather it is mostly small particles that are suspended in water. That is the reason that it still carries odor & color, and the remaining 20% is why you want the tank well filled before dumping. If you were to test the liquid from a natural black tank, you would find that much of that matter could be strained from the water with a very simple filter because it is particulate, but suspended. Compare that to the effluent of a properly working septic system, where it takes about two weeks to complete and septic system is putting out clean (not yet potable) water. The effluent of a good septic system is clear, or nearly so and is 100% liquid with no particulate.

Remember that the drain field of a septic system works for years with no attention at all because the complete process puts out water that is at a quality level that would be usable to water fields and crops. The newest septic systems don’t use a drain field but are called “aeration” systems and the effluent is applied to a lawn or such via sprinklers. If you see one, notice that the water from it is clear and has no odor. That is what a septic system does when working properly. When such systems fail and destroy the drain field or aeration system, it is usually because there is particulate matter getting into it.

Were the septic system to put out the same thing as comes from a black tank, it would plug the drain field or the aeration system very quickly. Those who question the use of water only have long insisted that a black tank is not a septic system, and they are correct, but that does not prevent the very early stage of septic action from taking place there. The only part that we are concerned with is liquefaction. What happens in the natural black tank is very much like the earliest process in the first chamber of a multi-chamber septic system.

As long as it is liquid enough for things to flush out, that is all that we really care, but it is also the reason that no black tank should ever be emptied into a storm drain. If the septic action was complete, then it would be OK to use the storm drain, or anywhere that non-potable water can be safely emptied. As mentioned in a previous post, it is far from complete, but it is the septic action.

So the purpose of an RV holding tank is to hold the waste and liquefy it so it will conveniently run out the disposal hose.  Simple enough!  It is not intended to break down the solids via aerobic action like the septic tank.  Use plenty, plenty of water when you flush and a septic safe toilet paper that dissolves well and you should be good to go!

I would guess most people who have never spent a summer in sweltering heat

The dreaded murderer of septic tanks nation wide

understand what effect that has on your black water tank. The heat kicks the septic action (decay of waste products) into high gear and it starts to smell. The only thing I have found to thwart this odor is a quart of bleach mixed in a couple gallons of water and flushed in to the black water tank. it will stop the odor immediately by killing the bacteria. Will it kill the bacteria in your septic system as well? I wouldn’t doubt it is going to kill off a few thousand or million bacteria but it is certainly not going to render your septic system inoperable. Consider this from the Clorox website:

It’s wrong to call household bleach chlorine bleach because it has an entirely different chemistry. Household bleach is derived from sodium chloride – common table salt. Clorox purchases chlorine and makes household bleach by bubbling the chlorine into a solution of water and sodium hydroxide. During this process, all of the chlorine is converted to a sodium hypochlorite solution

Household bleach begins and ends as salt water in a fully sustainable cycle. There’s a significant difference between “bleaching”– the name often associated with the manufacturing of paper products — and household bleach.

During consumer use and disposal, about 95 percent to 98 percent of household bleach quickly breaks down. The remaining two percent to five percent is effectively treated by sewer or septic systems.

Bleach does not contaminate ground water because it does not survive sewage treatment – either in municipal sewage treatment plants or in septic systems. Thus, there are no harmful effects of bleach in the environment.

This past summer I had to use the bleach in the black water tank twice. Bleach used in moderation.

I have also researched the assertion that bleach tends to degrade certain plastics and make them “brittle”. Again, from the Clorox website:

The majority of Clorox® bleach products contain anticorrosion agents and, when used as directed, are safe for use on a variety of hard, nonporous surfaces, including stainless steel, plastics, glazed ceramics, glass, porcelain and other materials. Use bleach with confidence to clean and disinfect countertops, floors, toilets, sinks, trash cans, keyboards, phones, light switches and desks.

In closing, let me reiterate that the bleach use I am advocating is based on personal experiences over the years. I am not a chemist or an engineer. Each of us has the freedom of choice and action to add whatever (or nothing) to their RV wastewater systems.

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