Basic Holding Tank Care and Drainage

11 July 2018

We know a lot of campers dread or even fear dealing with their holding tanks. The truth is, the task itself is pretty straightforward and simple. In the video below, our Orientation Technician Chris quickly explains how to drain your tanks while hooked up on campsite.


Step 1: Put on gloves and remove the cap to the tank drain opening. Hook your sewer hose (we recommend a heavy duty sewer hose like RhinoFLEX as it will last longer) up to the bayonet fitting. 

Step 2: Hook the other end of your sewer hose up to the dump station hole using a hose ring and elbow to prevent spraying.  

Step 3: Once you have the hose in place, first pull the black valve open. This will drain the black tank or sewer tank. You always want to drain the black tank first so that you can flush your hose out with the grey tank water after.

Step 4: Once you hear the black tank drain slow to a trickle, you can then open the grey tank valves and drain them completely.

Step 5: Once you've drained your tanks, close all of the valves. Some campers make the mistake of thinking that they can leave their valves open during the duration of their stay and the tanks will drain themselves. This isn't true. Pressure must build up within the black tank in order to allow for solids to flush completely, and without this pressure you may create a blockage. (We know. It's gross.)

Step 6: Disconnect the sewer hose from the trailer and lift the hose into the air to allow the remainder of the liquids to drain into the dump station. If possible, spray fresh water down the hose to flush out any residue. Store your sewer hose away from any other camping gear or tools if possible.

Sensor cleaner

If you've emptied your tanks and your gauges are still reading as full or partially full, you may have residue on the interior walls of the tank blocking the sensors.

This is a common problem that most RVers will experience at least once.

We sell Thetford Level Gauge Cleaner in our Parts Stores, which can be used to clean blocked sensors or with regular use, prevent a problem from occurring.

If you've tried cleaning the sensors and are still having issues, you can book an appointment to have your tanks cleaned and inspected by Stone's RV service department. 

For regular tank upkeep and maintenance, be sure to use enzyme-based deodorizing chemicals to breakdown waste and prevent smell. Once your tank is emptied, flush the toilet enough times to cover the bottom of your tank with water (usually 4-5 times) and then add your chemical and flush again. Now your black tank is prepped and ready for another trip! 

 Always, always, always (have we said it enough?) use toilet tissue specifically designed for RV use. This tissue breaks down in the holding tank chemicals, unlike regular toilet tissue which can clog your lines. You never want to flush sanitary products or paper towel down an RV toilet as this can cause major issues for the same reasons.

Be sure to check out our selection of holding tank chemicals, sewer hoses and RV toilet tissue at Stone's RV, and as always, never be afraid to ask questions! We're here to help.



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What our customers are saying

“Service after the sale is important to me and Stones proved that THAT is what they are all about. This past weekend we were camping in Antigonish and it torrentially rained on Saturday, and I noticed that there was water coming down the wall on the dinette slide. I called Stones immediately. About 3 minutes later Jonathan was at the door!” ~ Wayne and Arlene Cass