Begin RV

RV Black Water

What is RV Black Water?

RV black water is the human waste collected from the toilet. After a camper uses the toilet, the waste and water flush into the black water tank for storage. The RV black water tank can be emptied through a black water hose at a dedicated RV sewage dump. 

Woman emptying black water
Photo By: Madnruss. Licensed under the Creative Commons Attribution-Share Alike 3.0 Unported license


  • Having an RV bathroom is convenient but requires additional maintenance.
  • Taking preventative care measures will prevent costly mistakes.
  • Understand the basics of emptying and cleaning the black water tank.


Understanding RV Black Water

Most large motor homes and many smaller recreational camping vehicles are equipped with a dedicated bathroom containing a toilet.  Having a bathroom on the road is a major convenience and offers a greater privacy level than a public restroom. While having a personal commode provides a greater level of creature comfort, it involves extra work and planning to ensure orderly operation. 

RVs generally have three holding tanks: (1) a fresh water tank (2) a gray water tank and (3) a black water tank:

  • The fresh water tank holds the clean water for use in the shower, sink or for other fresh water uses; 
  • The gray water tank holds the dirty water from the RV shower or RV sink; 
  • The black water tank holds human waste and other content that flush down the toilet. 

Black Water Holding Tank Maintenance

Proper preventative maintenance measures are essential to keep the black water tank running properly.  Below are the steps that need to be taken to ensure proper maintenance: 

Fill With Fresh Water

A RV toilet is different than a home residential toilet as it does not have a water storage tank to assist in flushing the toilet.  Therefore, prior to use, it’s essential to fill the black water tank by dumping at least two gallons of fresh water down the toilet. Having a solid base of fresh water will help flush waste and prevent blockages. 

As a rule of thumb: there always needs to be water in the tank to cover the contents. 

Add Cleaner to the Black Water Tank

It is essential to add tank cleaner to the black water tank. Cleaning additives are available online, in most large supermarkets and specialty camping/outdoor supply stores. These chemicals allow solid waste to break down more efficiently to prevent clogs. Additionally, they come in several scent varieties to help keep your bathroom smelling fresh and clean.

Use RV Toilet Paper

The only items fit to be flushed down an RV toilet are: water, human waste and RV-specific toilet paper. Flushing items like q-tips, paper towels, regular household toilet paper, diapers, etc., can clog the holding tank which may require costly professional repair.  

It’s critical that only RV-specific toilet paper is dispose in an RV toilet. RV toilet paper breaks down rapidly to ensure that the black water holding tank does not clog. 

Emptying the Black Water Tank

For personal safety, it is recommended to wear latex gloves and eye protection when emptying the black water tank.  

The black water tank comes equipped with a sensor to measure the level of waste, which will indicate when it needs to be emptied. The instrument panel can typically be found close to the bathroom with indicator lights showing the fill levels.

When indicators show the black water storage tank is full (or close to full),  it is time to locate a dump tank at a dedicated RV dump station. Campers will need a black water hose which is a section of tubing used to connect the RV tank valve to the sewer hole. 

At full hookup sites, the sewer dump hole is usually located near the electric connection. At a site without full hookup access, dump stations are typically in centrally located areas. Dump stations can be located on a site map, by asking a camp host or by calling the front desk or ranger station. 

To empty the black water tank remove the RV valve cover, connect the hose and attach the other end of the hose to the sewer hole. The end connected to the sewer hole has an elbow connector, which is typically clear. The reason for the elbow being clear is so you can easily see when the tank has finished emptying.

Next, open the valve and allow the black water to drain completely into the sewer hole. 

Cleaning the Black Water Tank

After the black water tank has emptied it should be rinsed and cleaned. If build-up remains it can harden on the tank walls and block the sensor that reads the tank fill level.

After emptying the black water tank, it’s good practice to empty the gray water tank. The gray water tank collects the water from the shower and sinks, so it’s mostly filled with soapy water. Running the soapy water through the black water sewer hose will help to rinse out anything that’s gotten stuck. 

Finally, flush the tank with clean water and cleaning additives. You can use gallon jugs or a hose connected to a fresh water source. Some campers like to take a short drive during this step. The RV motion will agitate the water which will help dislodge anything stuck to the tank walls. 

Once you’re finished, thoroughly rinse the inside of your sewer hose. Use the water connection at your campsite or run a hose from a faucet inside your RV. 

Storing Your Black Water Hose

Keep the black water hose in a dedicated storage area away from any other hoses. Some RVs have a sewer hose compartment, but it’s recommended to use a plastic container with a locking lid. A sewer hose is not sanitary to keep around your belongings or hoses you use for other purposes, such as fresh water.

Related RV Terms

For related RV terminology, please reference the RV definitions below:

  • Gray Water: Used water collected from shower and sink drains, which is stored in the gray water tank.
  • Fresh Water: Clean, drinkable water pumped into the RV from an outside source or stored in the fresh water tank and supplies faucets and toilets.
  • Full Hookup: A campsite with amenities to connect an RV to fresh water, electricity, and wastewater dumps.
  • Shore Power: The connection of electricity to the RV from an outside power source like a campsite’s electrical pedestal. 

Like It? Go ahead and share!