Is Dumping Gray Water from Your RV Legal?

If you are boondocking, your gray water tank is likely to fill up more quickly than your black tank. You may also have noticed that some of your fellow boodockers dump their gray water on the ground. Whether or not that is illegal depends on where you are; some jurisdictions allow it, and others do not.

However, the best course of action is to assume that it is not legal. The best place to dump your gray water is always at a dump station.

Gray Water and National Forests

Surprisingly, dumping your RV’s gray water in a National Forest is allowed; however, it seems as if the USFS assumes that campers will only dump a very small amount, such as a washbasin full, and not an entire tank full.

Here are the rules for a National Forest:

“Old dishwater shouldn’t be dumped just anywhere. Carry gray water at least 200 feet away from lakes or streams and only use a small amount of biodegradable soap.”

You’ll notice, the most important point is to not dump your gray water into a freshwater source. Likewise, if you must dump your gray water, use biodegradable soap. That said, if you must dump your gray water in a National Forest, only release a little at a time, and use biodegradable soap.

Another good way to get rid of your gray water is to drain some into a bucket and use it to put out your campfire. Remember, the bucket you use should never be used for freshwater, once it’s been contaminated with gray water.

Gray Water and the BLM

It’s generally not illegal to dump your gray water on the ground of public lands managed by the Bureau of Land Management. However, in developed BLM manages campgrounds or wildlife preserves, dumping gray water may be prohibited. You’ll have to check on your location. Likewise, there are different rules for different states; For example, dumping gray water on BLM land in Nevada is not allowed.

On all public lands, no person shall, unless otherwise authorized, drain sewage or petroleum products or dump refuse or waste other than wash water from any trailer or other vehicle except in places or receptacles provided for that purpose.

“Gray Areas”

The regulations around dumping gray water also vary from state to state, as does the definition of gray water. For instance, in Arizona, you can dump “wash water” onto the ground; but, the state of Arizona defines wash water as clothes washer water or shower water, not kitchen sink water. The bits of food and grease in kitchen sink water is considered by Arizona to be sewage.

So while you may interpret the Bureau of Land Management or Forest Service rules as saying it’s OK, you could still get in trouble with local jurisdiction. The fact is, every one of the 50 states has different laws when it comes to dumping gray water.

Balancing Your Gray and Black Tanks

One of the best ways to manage your gray water is to dump some of it down the toilet. This will help keep the black and gray tanks more evenly balanced. For example, you can wash your dishes in a small plastic tub, then use that used wash water to flush the toilet. Another benefit to that is the soapy water will also help to break down the waste in the black tank and help keep it cleaner.

If You Must Dump Gray Water


If you absolutely can not get to a dump station, use a sewer cap with a hose attachment to dump your gray water. Keep in mind, you must have a hose dedicated only to gray water dumping; never, ever use your freshwater hose to dump gray water!

Simply attach the hose to the sewer cap, twist the cap onto your sewer outlet and direct it away from your RV onto the ground or into some bushes. Then, just open the valve. If you have a lot of gray water, just open the valve a little bit, to allow it to release slowly. This will give the ground time to absorb it. Do not just pull the valve open, and allow it to pour out onto the ground; this will simply create a muddy hole. Remember, leave no trace!

Of course, it’s better to balance your gray and black tanks, and get to a dump station instead.

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