Most RV’s have at least two waste holding tanks. Black tanks hold sewage and sometimes waste water. Gray tanks hold only waste water from showers and sinks.
Do not leave the black-water tank valve open when hooked up at a campsite. This will cause liquids to drain, leaving solid waste behind to harden on the bottom of the tank. Do not dump the black-water tank until it is at least two-thirds full.
Have the right tools on hand when you reach the dump stations. Always try to store hoses and connectors in an enclosed, segregated place to avoid contact with any other items and avoid cross contamination. Here is a list of recommended items:
Disposable gloves for handling the sewer hose
A heavy-duty sewer hose about 10 feet long for easier handling. Depending on where you dump, a longer hose may be necessary, or a connector between two hoses.
Sewer adapter to connect the hose to the valves. Clear is nice to know when your tanks are empty.
90 degree bayonet fitting, 45 degree fitting, or straight fitting for dump station opening.
A rinse hose for cleaning your black water flush. Never use your fresh water hose for rinsing sewer hoses or the dump station area.
Here is how to empty your RV’s holding tanks.
Pull up to the RV dump station with your holding tank drain valve as close to the opening of the dump station as possible. This will ensure that if there is a spill it will be contained in the dumping area.
Put on latex or other disposable gloves.
Unlock and open any compartments that you need to access for dumping the tanks.
If you have a permanent-mount black tank rinse system, connect it to the dump station water supply with the dedicated hose. Do not turn on the water yet, your tank may overflow into the RV.
Ensure both the gray and black water valves are both closed. Remove the holding tank outlet cap and connect your three-inch sewer hose to the outlet of your holding tank. You can tell if it is secure when the tabs on the adapter are lined up with the stubs on the tank drain. Tug gently to make sure it is secure.
Extend the hose to the opening of the dump station, which is usually a hole in the ground that is slightly larger than the three-inch hose. Insert the coupler into the dump station hole or insert your sewer hose into the dump station’s hole about four to six inches. Use the hole’s cover, a brick, or something heavy enough to hold the sewer hose in place so it does not come out of the hole and big enough that it will not fall down the hole.
Once you are sure that all is securely connected and held down, open your black tank valve. You will hear the effluent flow and eventually it will slow, then stop. Close black tank valve. When emptying black and grey tanks, dump the black water tank before the grey water tank so the water from the grey tank can clean the residue from the hose.
Turn on the water to the black tank flush and let run for several minutes, be careful not to overflow the tank. If you do not have a permanent black tank flush, use a portable flushing wand to clean out the tank. Turn off the water, open black tank valve, empty tank and close the black tank valve.
Open the gray tank valve. Again, you will hear water flow, then slow, and stop. Close the gray tank valve.
Recheck that both your black and gray water tank valves are completely closed. Disconnect the sewer hose from your tank outlet. Replace the tank outlet cap. Lift the end of the sewer hose that was connected to your RV to completely drain the hose into the dump station.
Remove your water hose from the RV if it is connected to the black tank flush, otherwise connect your hose to the non-potable faucet. Run water through the sewer hose to rinse it out.
Remove the sewer hose from the dump station hole and rinse the outside of the hose.
Rinse the area around the hole to ensure that any spillage has been cleaned up and cover the dump station hole. Turn off the water.
Return all your equipment to their storage compartments.
Dispose of the latex gloves into the garbage can or put them in your garbage can in the RV. Wash your hands just in case the gloves leaked. Never put anything other than the contents of your holding tanks into the dump station.
If there is a line up, move your rig to allow the next user to use the dump station.
Go in to your RV and add about five gallons of water (about three flushes) to your black tank and then add the appropriate amount of holding tank treatment. Use plenty of water in the black holding tank to reduce odor and to make dumping easier.