Finding Replacement RV Low Point Drain Caps (What Size?)

The purpose of the low point drains is to make sure you can empty your RV of water. Not just the water in your tanks but also in your water lines, and pipes. These drains are at the lowest point for your RV which could be anywhere on different models.

These are simple little caps that screw on the ends of the low-point drains. The caps should be found at any big box store that sells plumbing supplies for RVs. Or check Camping World and similar RV parts and accessories outlets.

To learn more about these drains and their caps, just continue to read our article. It contains the information you want to know about so you can find the right part for your RV or trailer.

What Size is a Low-Point Drain?


Generally, these little drains are only about 1/2 inch in diameter. There may be some larger sizes depending on the make and model of your RV or trailer. One owner said his was 2 1/2 inches in size but that may be an exception and not the rule.

When you are looking for a cap to close off these drains, there is one for the cold and one for the hot water lines, you should be able to find them just about anywhere.

Plus, you can find them in plastic to metal adapters if you want a metal end on your drain. Since this is a common part on all RVs and trailers, you should have no trouble finding what you need.

Also, the low-point drains may come with compression washers and if you replace the caps with a valve you can discard them. But if you are going with the regular cps you may need to continue to use them.

RV Low Point Drain Caps Options


Just one look at Amazon and you may be overwhelmed by the variety of drain cap options that are available for you to choose from. There are some drain caps that do reach 3 inches in size so if your low point drain is larger than 1/2 an inch you are not out of luck.

You can find the larger drain caps at Amazon and other RV parts outlets. In the caps alone, you can find 1/2-inch drain plugs in white, black, and even gray colors so you can match your pipe colors if you want to.

But these are not the only options you have available. There are a variety of NPT valves that will make using the low point drain a lot more fun and a lot easier. Instead of taking the cap off, you just turn the handle and the water will drain nice and easily.

These NPT valves come in plastic, chrome-plated metal, and brass. If you want to go with metal there should be enough plastic to metal adapters to help you make the conversion.

We should also mention that you can always cut the female end off of the drain and attach a Sharkbite valve to the water line. This is an option some owners have gone with.

Buying Low-Point Drain Caps


The only way to buy these little parts is to know the exact size you need and then go to your local hardware or Big Box store and see what they have in stock. These are a common part and you should be able to find them just about anywhere plumbing supplies are sold.

There are a variety of brands for you to choose from. Rec-pro, Camco, Zurn, and Flair-It are just a few of those brands. Not to mention all the generic universal caps made by less well-known companies.

Flair-It sells their caps for roughly $6.90 for one while Rec-Pro sells 2 for $9.95. Camco is a little cheaper than Rec-Pro at $9.61 for 2. These prices are from Amazon so do not forget to factor in shipping costs.

You may be able to beat those prices at your local stores and Big Box outlets. More elaborate designs for these caps will cost you a lot more even though they are made of plastic.

Expect to pay more when you buy the metal valve or cap options. One reason RV owners buy the metal caps is that they get longer use out of those metal caps than they would if they went with another plastic model.

Should Low-Point Drains Be Open Or Closed?


This will depend on how you winterize your RV. Of course, they need to be open when you are draining your water lines and tanks. Then closed when refilling your plumbing system with fresh water.

But when you are winterizing, you should open the drains when you are using compressed air to blow out the lines. Make sure to open the faucets as well at this time.

If you are not adding anti-freeze to your plumbing system, you can leave the drain open. This does not harm the RV except to let little animals find a nice place for winter.

But if you are adding antifreeze to your plumbing to protect against cold weather, you will need to close the low-point drains, both the hot and cold ones. Where you live in the country and how you store your RV will determine if you leave these drains open or not.

If you do leave them open when the RV or trailer is not in use, make sure to leave yourself a note to close them when you are ready to use the RV again.

Some Additional Words

The drain caps may be little and they may seem insignificant but they are essential parts to have on your RV. The good news is that every RV and trailer, for the most part, has these low-point drains and you can find replacements anywhere.

Just be prepared for a little sticker shock as while most are plastic, they can still cost more than you expect them to. But metal ones for longer life.

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