Simply dumping your black tank when it’s full isn’t enough to keep it clean and odor free. Cleaning and flushing the tank on a regular basis will prevent tank waste build up from forming inside. Excess tank waste build up can also cause tank level sensor failures and sewage line blockages. But a good cleaning will get rid of it.
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What You’ll Need To Clean Your Black Tank
You’ll need to keep a few things on-hand to help keep your tank clean. Here’s the list.
- A clear sewer hose attachment (see through)
- Water softener (I use Calgon Water Softener)
- Eco Friendly Detergent (laundry or dishwashing soap)
- Bleach (optional)
How to Clean Your RV Black Tank Step-by-Step
Start with an empty tank and have your RV parked next to a sewer hookup. This process requires you to fill and dump a few times.
1. Close the dump valve
You want to be able to fill the tank.
2. Fill the toilet bowl with water
Let the water fill the bowl without flushing (yet). You’re basically going to use your toilet as a mixing bowl.
3. Add water softener and detergent to water
Pour 2 small cups of water softener and 2 cups detergent into the toilet bowl. You could also add a little bleach if you feel comfortable doing so.
4. Flush the toilet into your empty tank
The combined cleaning solution and water should mix better when dumped into the tank together.
5. Fill the tank with water
There are several ways to do this. If you have a tank flush feature, then connect a hose to that. If not, you can fill the tank by sticking a tank wand into the toilet hole. Monitor the level until the tank is full.
6. Let it sit for a while before dumping
The goal here is to loosen up any build up on the walls of the tank. The longer you let it sit, the better. I typically leave it in for about an hour or more. So it’s best to do this at a full hookup campsite for best results.
7. Attach the sewer hose with clear attachment
Using a clear hose attachment is necessary to see what’s coming out when you drain the tank.
8. Dump the contents of the tank while watching the water passing through
The clarity of the water will tell you how clean or dirty the tank is. If the water gets clearer as the tank empties, then you’re on the right track.
9. Repeat these steps until the water runs clear
If the water that’s draining runs pretty clear, then you’re done. If you still notice some debris or brown coloring, then repeat the processes again.
Result

If your tank is relatively clean, then you should see clear water after the second flush. A dirty tank may take more flushes.
How Often Should You Clean Your Black Tank?
Refill and dump the tank each time you dump if possible. Or flush it out every other time. Then give the tank a good cleaning every month or so. Just don’t wait for your tank to stink before taking action.
When dumping, keep the clear hose attachment on to watch what’s coming out of your tank. Once you’ve gotten into the habit of flushing your tank regularly, you should see clear water after just one flush.
How To Get Rid of Black Tank Smell Permanently
Keeping a clean tank is the first step to preventing black tank odor inside your coach. To get rid of black tank odors for good, I recommend you check out my other article 5 Ways To Get Rid of Black Tank Smell Permanently.