What is an RV low point drain valve and where is it located? Does every RV have one? What does it do?
A low point drain is an important part of an RV, and in this post, we tell you why. We cover what a low-point drain valve is, what it does (and what it doesn’t do!), why you need it, and where to find it!
What Is an RV Low Point Drain Valve?
Low point drains are designed to allow the water to drain completely from an RV’s water system. The primary reason you’d want to drain the water from your RV’s plumbing is to help avoid the risk of the lines freezing. As you might expect, low-point drains are situated at a low point in the plumbing.
There are typically two or three low-point drain valves in an RV (but not always). There’s generally one for the cold water side (often blue), one for the hot side (often red), and one for the fresh water tank (white).
Some small RVs have only a single low-point drain. In a Class B Roadtrek, for example, you drain the fresh water tank and the hot & cold fresh water system by opening the exterior fresh water drain valve at the single low point drain under the RV. Other small RVs may operate similarly.
Where Is the Low Point Drain On an RV?
Usually, you can find them by looking under the RV for short tubes or pipes sticking down toward the ground. Sometimes the drain valves are right there on the drain tubes/pipes and simply need to be twisted open.
In other cases, the valves are located somewhere inside the heated underbelly of the RV, to help protect them from freezing when you’re camping in sub-freezing temps. So, in some cases, to open the low point drain valve you may need to follow the tube or pipe upstream to where the valves are located.
Does the Low Point Drain Empty the Water Heater?
No. The water in an RV’s hot water tank is NOT released by opening the low point drain. If an RV is equipped with a tanked water heater (Suburban or Atwood), the tank will need to be drained separately. Low-point drains only drain the plumbing lines, faucets, valves, etc.
To drain your RV’s hot water tank, you would open the pressure relief valve on the water heater, and then remove the anode rod (Suburban) or the drain plug (Atwood) and allow the tank to drain.
For much more information on this process, see our post on how to flush your RV water heater or check out our YouTube channel to follow along with us step-by-step as we drain and flush a tanked hot water heater and show you how to clean out the limescale from the bottom of the tank and from the heating element to keep your:
How to Drain an RV Plumbing System Using the Low Point Drain
To drain your RV’s water system thoroughly, take the following steps:
- Turn off the city water or your RV water pump (depending on whether you’re connected or not).
- Open all faucets inside the RV, and turn the water to warm to allow air from both the hot and cold sides into the plumbing as it drains.
- Open the low-point drain valve(s).
What If My Low Point Drains Don’t Have Valves?
Not all RVs come with actual “valves” that need to be turned to open/close them. Instead, some use a screw-on cap. If your RV has caps, leave your faucets closed until you remove the cap(s). This will help keep all of the water from draining right away when you remove the cap. Once you’ve removed the cap, then go inside and open your faucet(s) to allow the plumbing to drain.
You can also consider adding actual valves to your setup, making it easier to use the low-point drains in the future. The following valves should work, but confirm the size of your existing drain plumbing to be sure they’ll fit.
½” FIP (Female Inner Pipe thread) PVC Ball Valve – Red
- ✔LEAK-FREE: Female Threaded Ball Valve Includes EPDM O-Rings and TPE Seats for a Secure, Leak-Free Seal
- ✔RED HANDLE: Enables Rapid and Safe Flow Control in Your Water Pipes; Not Recommended for Potable Water
½” FIP (Female Inner Pipe thread) PVC Ball Valve – Blue
- Leak-Free: Female Threaded Ball Valve Includes EPDM O-Rings and TPE Seats For a Secure, Leak-Free Seal
- Blue T-Handle: Enables Rapid and Safe Flow Control in Cold Water Pipes; NSF Certified for Potable Water
The valves are also available at most major big box hardware stores or good plumbing supply stores. Again, be sure to check the size of the pipe/tubing you need to connect to and take note of how it connects (most are likely threaded in place, but some may be clamped or glued in place instead).
When to Use Your RV Low-Point Drain Valves
You use your low-point drains when you winterize your RV. This removes the water from the plumbing system before pumping in the antifreeze. If you don’t do this, the antifreeze will be diluted by the water in the system, reducing its effectiveness/protection.
If you use compressed air to blow out your water lines during the winterizing process, you would still use your low point drain to first drain the water from the system.
For more information, see our posts on how to winterize an RV with antifreeze and how to winterize an RV with an air compressor.
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Mark
Thursday 23rd of October 2025
Is there water pressure at the low point drains when the pump is on? If so, I am interested in hooking up a standard hose connection to the cold water drain, including a valve, to connect the other end to the black tank flush inlet. There are times in mid to late fall that campgrounds have already shut their water off at the dump station for the winter. I'd like to use leftover water in the fresh tank to do that.
TheRVgeeks
Thursday 23rd of October 2025
Hi @Mark. Yes, there usually is pressure at the low-point drains, as they're just plumbed into the RV's plumbing system like everything else. Just low. 😉 Adding a hose connection there is a really great idea for your use case!
Sid
Saturday 21st of June 2025
I have a travel trailer and temps supposed to dip to 25-32 degrees for about 8 hours overnight. We have exposed hot and cold low point drains. Do we need to drain the system as you described in this post?
Sid
Saturday 21st of June 2025
Thank you very much for your quick and helpful reply!
TheRVgeeks
Saturday 21st of June 2025
Hi Sid! All RVs have low point drains that stick out underneath, so the fact that the drains themselves are exposed should be okay, since the water below the valves always drains out anyway. In general, a short exposure to the temperatures you're expecting shouldn't cause a hard freeze that you need to worry about, especially if it's going to only be down to as low as 25 for a couple, or a few, hours during the coldest part of the night. If you have a well-insulated rig that's comfortable to camp in during temps in the mid-20s, your best bet is to keep the heat on to keep the trailer interior warm. If you're comfortable inside, you should be good for this short cold period. All that said, 25 is indeed below freezing, so it's not impossible for pipes to freeze. But it does sound like you should be okay with the heat on, unless your rig is very poorly insulated, in which case you wouldn't likely be comfortable in it when it's this cold anyway.
Moe Trujillo
Monday 27th of January 2025
how do you change out the valves , both red and blue, when leaking. And how do you know what size are the lines?
Jeri
Monday 27th of January 2025
I’m full-time stationary….city water, not tank…do I need to drain or winterize? Thank !
TheRVgeeks
Monday 27th of January 2025
Hopefully, Jeri... you're also full-time INSULATED. And how well depends on how cold it gets during the winter. The biggest risk to the plumbing in winter is for it to freeze, and the expansion that happens when water goes from liquid to solid can result in burst fittings and/or pipes. If your unit/RV is built in with skirting and heated fresh water line(s), etc you should be fine. But if you're parking your trailer/motorhome for a stationary winter, you're going to want to be sure you're taking all the necessary precautions to keep plumbing from being exposed to sub-freezing temps for too long. Check out these articles for more: How to Live in an RV in Winter, Tips for Winter RV Camping, and Winter RVing in Freezing Weather — Cold Climate RV Survival Tips
Richard
Monday 27th of January 2025
Have hot and cold shut off. I open both to drain tank however I have to run the pump to drain the tank . I would think gravity would do it ? Is this normal ?
Richard
Monday 27th of January 2025
@TheRVgeeks, thanks guys, I had no idea there another drain. I sent a email to my coachman contact to let me know where that might be located.
TheRVgeeks
Monday 27th of January 2025
Hi Richard. Yeah, that sounds normal. The low-point drains are for draining out water from the RV's plumbing lines for winterizing, etc. They're not (usually) plumbed to be the way to drain the fresh tank. There's often a third drain (white) that's for draining the fresh tank, but it can be hard to find. On our Newmar Motorhome, it was hidden deep in the wet bay, behind all the plumbing hookups. On our new travel trailer, it's up underneath the trailer, near where the fresh tank is mounted in the chassis.
Look around, or check your owner's manual, to see where your fresh tank drain valve is located.