Black Water: a Newbies Guide

With an Airstream hooked to the back of your car you’ll find that long trips are much nicer. One perk is having your own bathroom wherever you go. There’s only one small price to be paid for this convenience: dumping the waste tanks.

Black vs gray: Blackwater is sewer water from the toilet, which in most Airstreams is held in a separate tank from the gray water (used water from the sinks and shower).

Airstream bathroom

Be not afraid. If there’s one thing that keeps people away from RVing it’s the fear of dumping the holding tanks, but dumping the tanks is as easy as can be. You attach a simple hose, pull a handle, and—whoosh!—your troubles are flushed away. First the black tank, then the gray tank.

Wash your hands whenever you’ve touched the sewer hose. Some people like to wear disposable gloves, but you should wash your hands thoroughly afterward in any case.

Pay attention to your holding tanks, and to a certain extent what goes in them. The black tank should only contain things you’ve previously eaten, easily-dissolved toilet paper, water, and a bit of tank chemical to help things along. Nothing else.

Wear gloves as an option.

Tank chemicals (often called “sanitizers” or “digestants”) should be added to the black tank every time after it is dumped, along with a gallon or two of water. These chemicals help break down and liquefy the waste, which is what you want for trouble-free tank dumping.

Avoid formaldehyde. We recommend you choose tank chemicals that don’t use formaldehyde. Formaldehyde kills the beneficial bacteria that help break down the waste. Not only is that counter-productive for you, but it can prevent septic systems from working, which causes problems for campground owners. Formaldehyde is also a known carcinogen. Products labeled “bacterial digestant”, “enzyme based”, or “septic safe” are the best choice.

Add water. Don’t be too skimpy on flushing water from the toilet into the black tank. The tank needs a good ratio of water to solids in order to empty properly. Failure to add sufficient water will result in “buildup.” You won’t like that.

TP options: There is special “RV toilet paper” that is sold in RV stores. It’s much more expensive than the household variety. It works, but you will also do well with a single ply toilet paper, such as Scott’s, which is available in grocery stores across the country.


Sewer hoses don’t last forever. To avoid disasters of the worst possible sort, replace that hose at the very first sign of cracking, pinholes, or any sort of wear. People who wait for the hose to fail usually regret their choice.

Excerpted from Rich Luhr’s definitive book for all owners, “The Newbies Guide to Airstreaming”, available at amazon.com and the Airstream Life Store.