The BIG question…should you keep your RV gray tanks open or closed?

Every RV owner has their own personal spin on how they maintain their RV tanks.

In fact, it is quite a big debate amongst RV owners from newbies to seasoned RV Pros… but, what’s the truth?

Open and Closed RV Tanks

We’ll get to the truth but let’s first discuss the cause and contents of a typical RV gray tank.  WARNING…it is way more than just soapy water, which is a common myth amongst RV owners. 

The “CAUSE” – Try not to lose your lunch!

HairShaving Cream
Food ParticlesToothpaste
Soap ScumGrease Residue
Black Mold


  • Foul Odor – typically emits from sink and/or shower drains
  • Inaccurate Tank Sensor Readings
  • Sewer Flies & Larvae – which can hatch and fly up through your sink/shower drains
  • Costly Clogs – caused by mold overgrowth and mold plugs

And now….


To ensure the proper function of your RV’s gray tanks, they should ALWAYS be kept closed with at least three to five gallons of water in each gray tank.  

Right about now you’re probably asking, “What about laundry days, or episodes of high-water usage”? 

Well, that’s easy! Simply leave the RV gray tank open during times of high water usage and remember to close them once you’re done.


Every RV owner desires to maintain the proper function of their RV tanks.  We have all heard the old saying an ounce of prevention is worth a pound of cure, and so it is for the health of your RV tanks!

Here is our short list of QUICK TIPS for maintaining your RV Gray Tanks:

  • Keep your gray tank valves closed until you are ready to dump.
  • Always keep 3 to 5 gallons of water in each of your gray tanks.
  • Consider using a gray tank additive such as Liquified Gray tank treatment. 
  • Consider having Tank Rangers perform an annual RV tank cleaning to maintain the health of your RV tanks.
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Tina Arnold


Social Media – Content Creator

We are fellow RV’ers who love serving our RV community!