If you have an RV, you know that there are a lot of moving parts – and each one needs to be in good working order for your travels to be enjoyable. That’s why it can be so frustrating when something goes wrong, like your grey water tank not draining.
There are a few different reasons why this might happen, but don’t worry – we’ll walk you through some common causes and what you can do to fix them. Read on to learn more about why your RV grey water tank might not be draining properly, and what you can do about it.
What Is the Grey Water Tank?
Before we get into troubleshooting, let’s first make sure we’re on the same page about what the grey water tank is. In short, the grey water tank is where all of the water from your RV’s sinks and showers goes – that means anything other than toilet waste.
When you flush your toilet, the waste goes into a separate black water tank. But when you wash your hands, brush your teeth, or take a shower, that water all flows into the grey water tank. Once it’s full, it needs to be emptied so that new water can continue to flow in.

Common Causes of an RV Grey Water Tank Not Draining
There are a few different reasons why your RV’s grey water tank might not be draining properly. Here are some of the most common causes:
How to Fix an RV Grey Water Tank That Won’t Drain
Now that we’ve gone over some of the most common reasons why your grey water tank might not be draining, let’s talk about how you can fix it. Here are a few steps you can take:
- Open the valve all the way: If you think the valve might not be fully open, the first thing you should do is check to make sure it is. This is usually a pretty easy fix.
- Clear the hose: If there’s a blockage in the hose, you’ll need to clear it before the water can flow through. The best way to do this is to disconnect the hose and flush it out with a garden hose.
- Check the pump: If your RV has a grey water pump, make sure that it’s plugged in and getting power. You may also need to replace the pump if it’s not working properly.
- Thaw the tank: If your grey water tank is frozen, you’ll need to thaw it out before it can drain. The best way to do this is with a space heater or hair dryer.
Tips for preventing a blocked or non-draining grey tank
Now that you know how to fix a grey water tank that’s not draining, let’s talk about how you can prevent it from happening in the first place. Here are a few tips:
- Don’t put anything other than water down the drain: This seems like common sense, but it’s worth mentioning. Anything other than water – including soap, food, and grease – can cause a blockage in the hose.
- Use biodegradable soap: If you do need to use soap, make sure it’s biodegradable. That way, it won’t cause as much of a build-up in the hose.
- Run hot water before draining: This will help to break up any soap build-up and make it easier for the water to flow through.
- Use an RV grey water treatment: These treatments help to break down waste and prevent build-up in the hose. They’re available at most RV supply stores.
Conclusion
We hope this article has helped you troubleshoot the issue of your RV’s grey water tank not draining. Remember, if the valve is not open all the way, there’s a blockage in the hose, the pump isn’t working, or the tank is frozen, you’ll need to take action to fix the problem. With a little bit of effort, you should be able to get your grey water tank draining properly again in no time!
FAQs
What should I do if my grey water tank starts to smell?
If your grey water tank starts to smell, it's probably due to a build-up of soap or other waste in the hose. The best way to fix this is to disconnect the hose and flush it out with a garden hose. You may also need to use RV grey water treatment to break down the waste.
Can I put bleach down the drain?
No, you should not put bleach down the drain. Bleach can damage the hose and cause a blockage. If you need to disinfect your grey water tank, use RV holding tank treatment that contains bleach.
Citations
https://www.forestriverforums.com/forums/f217/grey-tank-not-draining-204085.html
https://www.airforums.com/forums/f444/gray-water-tank-suddenly-not-draining-at-all-232639.html
https://www.jaycoowners.com/forums/f7/grey-water-tank-wont-drain-68283.html
https://www.rvforum.net/threads/gray-water-tank-wont-drain.105734/
Ever since I was a kid, I've been fascinated by travel. I inherited this passion from my parents. Since my college years and to this day, I have had a passion for traveling in a motorhome. I am here to share my experiences with you.