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How to flush Airstream black water tank

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Confused on how to flush Airstream black water tank?

Unsure of how or when to dump your black and grey water tanks?

Dealing with strong odors from the grey or black water tanks in your Airstream?

I’ll walk you thru step-by-step everything you need to know about how to dump and flush your Airstream black water tank.

What are the different Airstream RV holding tanks?

Most Airstream trailers have separate black and grey water tanks except for the smaller Airstream models like the Nest, Basecamp and Bambi trailers which have one wastewater tank that combines the black and grey water waste.

RV Black Water Tank

Your RV black water tank holds the water and waste from your toilet and is sometimes called a sewer tank, or “poop” tank as my Dad used to call it.

It is important to properly care for your black water tank to prevent the tank from clogging or from solid waste getting stuck in the tank after you finish emptying the black water tank.

If you’re in a campground with full hookups, don’t be tempted to leave your black and grey water tank valves open to drain into the campground sewer. The waste tanks work better if you allow them to fill up to about two-thirds full and then dump them. If you keep the waste tank drains open, solid waste can get left in the tanks and harden, which can lead to strong odors or clogging of the tank.

RV Gray Water Tank

Your RV gray water tank contains the water from the sinks and shower as well as soap, shampoo, toothpaste and any food particles that the sink drain didn’t catch.

Can I put food and coffee grounds down my RV sink?

It’s not recommended put let food, grease or coffee grounds down your Airstream sink since the food particles can cause bacteria to grow in the grey tank and lead to a funky, bad smell in your Airstream.

Bacon grease and other thick liquids and coffee grounds can also solidify in the grey water tank or clog the drain from the sink into the grey water tank.

Since the plumbing in an RV isn’t as hardy as your home plumbing, you run the risk of a cracked, leaking sink drain that can become a big hassle on your camping vacation.

So its best to throw the food scraps and coffee grounds in the trash (or even better, compost them) and save the bacon grease for cooking.

Why does my RV sink smell?

If you notice a strong odor or smell around either the kitchen or bathroom sink in your Airstream, you probably have some bacterial growth in the grey water tank. Just like your black water tank, you can use a RV tank water treatment like Happy Camper or Unique RV DIGEST-IT holding tank treatment. Both products are formaldehyde-free, which more RV parks are requiring if you want to use their full sewer hookups or dump station. The older holding tank treatments with formaldehyde can contaminant and leak out of septic systems into the ground water.

Can I dump my Gray Water tank on the ground?

The real question to ask is if it’s illegal to dump your RV gray water tank on the ground. The laws regarding gray water tank dumping varies state to state but most states have laws against dumping gray water tanks on the ground.

If you’re boondocking on BLM land or in a National Park, you’ll also have to contend with Federal laws as well.

One issue with open grey water tank drainage is that the soaps, detergents and food particles get left behind on the ground after the water soaks into the ground. The other issue is that the grey water can be contaminated with chemicals that could then leak into the local water aquifer and potentially contaminate the drinking water.

How to flush RV waste water tanks

Flushing your Airstream black and grey water tanks is a very easy and straight forward process. If you’re in a campground and on full hookups, you only need to dump your waste tanks when they get more than 2/3rd full.

I’ve noticed my grey water tank fills a lot quicker between water use in the kitchen and bathroom sinks as well as showering. One problem you’ll quickly find out is that the grey water tank will start to backup into the shower when its full.

It’s not pleasant to be taking a shower as you start to watch the bottom of the shower begin to fill with dirty kitchen sink water!

Step-by-step guide to dumping your RV waste water tanks

Tip – Make your mother proud and wear gloves if you’re touching the sewer hose.

  1. Make sure your sewer hose is firmly seated into the campground’s sewer drain.
  2. Check to see that the end of the sewer hose to the Airstream is also firmly connected to the sewer drain of the Airstream. The sewer hose has a bayonet head that twists and locks onto the outside of the Airstream sewer drain.
  3. Check the length of the sewer hose for any cracks or leaks. Also make sure that there is a continuous drop in the sewer hose from the RV to the campground’s sewer drain. (Remember “Sh*t always flows downhill.”) You can use a sewer hose support to help hold the sewer hose.
  4. Once you’ve confirmed that the sewer hose is attached, you can start to drain the black water tank first. On most Airstreams, the black water tank valve is on the right side of the sewer drain. You simply have to pull the T-shaped handle straight out away from the trailer and you should hear the tank start to drain.
Grey water tank valve on the left and black water tank valve on the right


5. Otherwise, let the black water tank continue to drain. Having a clear plastic bayonet connector between the sewer hose and the campground sewer drain is an easy way to know how quickly the tank is draining.

6. Once the black water tank finishes draining, close the valve to the black water tank by pushing the T-shaped black handle back toward the trailer. You should be able to push the base of the handle all the way to the edge of the tank.

7. Now open the grey water tank by pulling on the grey-colored T-shaped handle to the left of the Airstream’s sewer drain. You should hear more water draining from the holding tanks. The reason for draining the black tank first and then the grey water tanks is that the grey water will flush any sewage left in the sewer hose down into the sewer drain. This way if the sewer hose accidentally gets disconnected from the campground’s sewer drain at some point, there’s only a little grey water that gets spilled.

8. Once the grey watertank is finished draining, close the grey water tank valve the same way as you closed the black water tank valve, by pushing the grey handle back towards the trailer.

Tip – The black and grey tank valve handles are PUSH-PULL and don’t need to be twisted.

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Its also recommended doing a black water tank flush by using the outside sewer water connector. The Airstream black water tanks have spray nozzles at the top of the tank to help rinse out any remaining solids or toilet paper in the tank.

TIP – Don’t use your white drinking water hose for this. Use a separate hose. Most RV sewer water hoses are orange to help identify and keep them separate from the drinking water hoses.

Orange RV sewer flush hose with end cap to rinse large sewer hose

Once you’re finished draining both tanks, you can take off your gloves (and remember to wash your hands) and go inside to add some water and the holding tank treatment to each holding tank.

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