WTF - What To Flush

April 25, 2019

What can I flush down my RV Toilet - Flushable wipes, tampons, condoms, poop, pee, urine, rv toilet paper

What you allow down your sink and toilet drains has a big impact on preventing holding tank troubles - clogs and harsh odors. Building good holding tank habits will help you avoid these frustrating and expensive problems. In this article we will dive into what chemicals and products you should AVOID allowing in your holding tanks, so your RV trip isn't ruined by unexpected odors and clogs.


Key Points
  • Only allow human waste (poop and urine) and toilet paper down your black tank. No trash, plastics, flushable wipes, tampons, etc.
  • Do not allow food waste down your gray tank.
  • Beneficial bacteria is the best solution for preventing and controlling clogs and odors in your RV holding tanks.
  • Unclogging a plugged holding tank requires a strong enzyme-based cleaner.
  • Caustic chemicals, like chlorine, bleach, alcohol, formaldehyde, and oxidizing agents will kill beneficial the bacteria inside your holding tanks.
  • When the beneficial bacteria from bacteria-based holding tank treatments die off, the chances you will experience clogs and odors increases significantly.
  • If you want your holding tank to perform at it's maximum potential, you should:

    1. Avoid allowing caustic chemicals and food waste inside your holding tank
    2. Treat your tanks with a good bacteria-based treatment, like RV Digest-It
    3. Follow The Unique Method


What Should Be Allowed In My RV Holding Tanks?

Your RV black tank is one piece of a very sensitive water system. Some RVs have more sensitive waste water systems than others, but many RVers would probably agree; you must be diligent when you take care of your RV. It is all too easy for a clog or strong odors to put a wrench in your vacation, weekend getaway, staycation or full time living experience. Let's go over what items should and shouldn't be allowed inside your black and gray water holding tanks.


Your RV Black Water Tank

There are only a few things that SHOULD be allowed inside your RV black tank:

  1. Human Poop and Urine
  2. Toilet Paper
  3. Water 
  4. Non-hazardous RV Holding Tank Treatments

Anything other than this list (i.e. trash, plastics, toys and hazardous chemicals), can and often WILL, cause issues. Fortunately, maintaining a holding tank that is completely free of odors and clogs is pretty simple. Only allow the right things in your tank and use your tank correctly. The Unique Method is a comprehensive guide for treating RV black tanks and keeping your RV clog and odor free. 


Your RV Gray Water Tank

Just like your RV black tank, there are only a few things that SHOULD be allowed inside your RV gray tank:

  1. Water 
  2. Soap
  3. Non-hazardous RV Holding Tank Treatments

Grease, soap scum, and decomposing food are what cause gray tanks to have odors and misreading level sensors. It is important that you prevent food from getting into your gray tank whenever possible. Food (which causes grease) can wreak havoc on your gray tank. The water solution that is being held in your gray tank (if you leave your Gray Valve closed when camping) will deposit food residue and grease on the tank floors and sidewalls. This grease will coat your sensors and cause them to misread and it can even smell worse than your black tank!

Water, soap, and safe holding tank treatments are the only things that should go down your sink or shower. To keep food from getting into your gray tank we recommend using an in-drain sink strainer.

To maintain waste breakdown and a stink-free gray tank we also recommend treating your holding tank regularly with a bacteria-based treatment like RV Digest-It.

Sign up and get regular discounts on your favorite RV necessities. Unique Camping + Marine Holding Tank Treatments

Why Do Bacteria Matter?

Bacteria is a crucial part of the waste breakdown process. To put it plainly, without bacteria and enzymes, waste breakdown is not possible. Non-bacteria and non-enzyme treatments do nothing to break down waste and normally use odor-masking, caustic chemicals to "cover up" your stinky tanks. Our RV holding tank cleaners attack the odors and clogs head-on instead of disguising them with strong perfumes.


Chemicals To Avoid

Many RVers understand how important it is to choose the right RV toilet chemical when treating your holding tank, but few understand how important is to be aware of the other products you allow down your drains - like toilet cleaners, soaps, and detergents. These other products can negate the positive effects of your well-selected tank treatment and render them useless.

Many of the products that people use everyday, often unknowingly, may harm the good bacteria inside your RV toilet treatments and as a result, slow down the waste breakdown process in your RV holding tanks.

There are certain chemicals that will regularly kill the beneficial bacteria inside your holding tank. These include:

  • Alcohols
  • Antibacterial Soap
  • Bleach
  • Chlorine
    Formaldehyde (any aldehyde)
  • Iodine
  • Strong acids, like sulfuric acid
  • Very strong alkaline chemicals, like lye or sodium hydroxide.


It is also possible that antibiotics you are taking may have a negative effect on beneficial bacteria inside your holding tanks as well. 

These are the most common chemicals that can disrupt your holding tank and lead to waste buildup and odors.

If you want your holding tank to perform at it's maximum potential, you should:

  1. Avoid allowing the above mentioned items / chemicals inside your holding tank
  2. Treat your tanks with a good bacteria-based treatment, like RV Digest-It
  3. Follow The Unique Method
In Summary

RV waste water systems can be very sensitive at times and there is a healthy balance needed to keep your RV free from strong odors and clogs. Restricting the kinds of things you allow inside your black and gray tanks is only the beginning. It takes daily habits  to keep things running smoothly. Bacteria are a crucial part of your waste water systems and by using products that kill bacteria, you will increase the chances of maintaining a clog and odor-free RV. It was also help make your toilet treatments more effective, which will save you from flushing your money down the drain - literally!

Hopefully this article has helped you understand what you should and shouldn't allow flush into your RV holding tanks. Of course, if you ever need any help or if you have any questions, we're always happy to help! Just email us at



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