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What Is Black Water in an RV? – Important Facts to Discover

Writen by Tom Hank

Fact checked by Joseph Varney

what is black water in an rv

Using an RV means understanding its ins and outs, including what is black water in an RV.

Black water in a camper generally means the wastewater that comes from the RV’s toilet. Rig users shouldn’t confuse it with gray water, for that particular wastewater often originates from other appliances and fixtures like the sink and shower drain.

Continue reading to gain additional insight on black water in an RV. You’ll also learn other relevant pieces of information, such as how to keep a black tank from smelling, as you go through this post.

Table of Contents

What Is Camper Black Water

Black water is typically the wastewater flushed down the camping vehicle’s toilet. It generally gathers in the black water tank, which rig users should drain before this reservoir becomes full.

What Is the Difference Between Black Water and Gray Water


One of the main differences between black water vs grey water is their origins, as mentioned above.

Also, black water in a camper generally has more contamination than its gray counterpart. The reason behind that idea is that black water usually has urine and fecal matter.

However, it’s possible to recycle black water and repurpose it into fertilizer. But that particular wastewater should undergo the correct decomposing and processing procedures for users to take advantage of it on plants.

As for gray water, it’s possible to reuse this wastewater without relying on relatively any processing operations. It’s possible to pour gray water on vegetation without affecting the organic matter’s life adversely.

How Often Should You Empty Your RV Black Water Tank

Emptying a black water RV tank often depends on the size of the reservoir. But a general rule of thumb to follow is to dump this container at least once per 3 to 5 days.

Take note that some RVers may notice their 40-gallon black water tanks require emptying after a 10-day usage period. That means that a 50-gallon tank may allow rig users extra time before they need to dispose of their RV black wastewater.

How Do You Empty an RV Black Water Tank


Empty the RV black tank once its sensor indicates that the container is full. Keep in mind that each camping vehicle model may demand unique steps to drain its black water containers.

So, check your vehicle owner’s manual if you find yourself stuck at a particular step. Another option is to contact the camper manufacturer’s customer or technical service hotline for assistance.

After taking note of these particulars, here’s a general guide on how to empty an RV black water tank:

Quick Step-by-step Guide

  • Step 1: Park your camper at an RV wastewater dumping site.
  • Step 2: Locate and pull your RV’s black water tank valve open slowly.
  • Step 3: Wait until the container empties all the wastewater in it.
  • Step 4: Close the RV black water tank valve.

Take note that some RVs may require you to attach a hose to drain the black water properly. If so, some of these camping vehicles will already have a built-in drain hose. Otherwise, you might still need to purchase this accessory to complete this task.

How Do You Maintain Your RV’s Black Water Tank

Remember, following a proper maintenance routine for your RV’s black water tank will reduce the risks of certain issues. Failure to care for this reservoir may result in problems like leaks and off-putting smells.

Follow this general process to ensure your RV black water tank functions as intended:

Quick Step-by-step Guide

  • Step 1: Shut off the gray water tank valve to wash the sewer line later.
  • Step 2: Clean the RV toilet, then connect a garden hose to an anti-backflush valve.
  • Step 3: Turn on the black water tank valve slowly to remove excess liquid or moisture.
  • Step 4: Close the black water tank valve and the container should start filling.
  • Step 5: Open the tank’s valve again once the tank’s full.
  • Step 6: Once everything’s flushed out properly, pour an all-purpose cleaner down the toilet.

Frequently Asked Questions

1. How Do Black Water Tank Sensors Work?

RV black water tank sensors are probes typically found at the bottom of the container. These components generally have positive and negative parts, notifying rig users when the reservoir is empty or full.

This system functions by completing a circuit once it detects wastewater in the container has reached a particular level. However, the filth and muck in the black water tank may cause its sensors to fail, and cleaning may be required to restore their functionality.

2. Where Is The Right Place To Dump RV Black Water?

Keep in mind that dumping RV black and/or gray water in any other location besides certified areas can be illegal. Always check the locale for nearby RV wastewater dumping stations to avoid paying expensive fines.

Some of the locations you should consider for dumping your RV’s black water are:

  • RV parks and campsites
  • Rest stops
  • Gas stations
  • RV retailers

3. Will Bleach Harm An RV Black Water Tank?

If used properly, bleach may help disinfect your RV’s black water tank. Make sure to only use the appropriate amount of this strong disinfecting solution to avoid harming the container and its framework.

Ensure that you only use ¼-cup of bleach per gallon of wastewater in the tank. For example, if the tank has 20 gallons of black water, you should only use no more than 5 cups of bleach.


At this point, you should now have a good idea of what is black water in an RV. Remember, this wastewater usually comes from the camper’s toilet. That means that you shouldn’t use it for drinking or cleaning.

Also, proper dumping of RV black water will help prevent issues with the vehicle’s plumbing system. Improper black water disposal may also deliver expensive charges to RVers.

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