6 Best Expandable Drain Plugs That Simplify RV Water Shutoffs

Ever found yourself on your knees, fumbling with a plastic drain plug, trying to get the threads to catch while cold water drips down your arm? It’s a classic RV moment, and one of the small frustrations that can make a simple task like winterizing feel like a chore. Replacing that cheap, factory-installed plug is one of the easiest and most satisfying upgrades you can make. A good expandable drain plug eliminates the need for tools, thread tape, and cross-threading anxiety, turning a dreaded task into a 30-second job.

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Camco Twist-Tite: Top Pick for RV Winterizing

The Camco Twist-Tite is the go-to for a reason. Its design is brilliantly simple: a rubber plug that expands when you turn the T-handle. This direct, tool-free operation is exactly what you need when you’re draining your water heater as part of your winterizing routine. You don’t have to worry about finding the right wrench or stripping a plastic hex head.

This plug is specifically designed for the low-pressure environment of an RV water heater drain. You insert it, give the handle a few turns until it feels snug, and you’re done. The rubber gasket creates a positive seal against the inside of the drain port, preventing leaks without relying on fragile threads. It’s a purpose-built tool that solves a very specific RV problem exceptionally well.

The key is understanding its limitation. This is not a high-pressure plug. It’s made for gravity-draining a tank, not for capping a pressurized line. But for its intended purpose—making water heater maintenance fast and painless—it’s the undisputed champion.

Valterra T1020-1VP: Best for Easy Installation

Think of the Valterra plug as a close cousin to the Camco. It operates on the exact same principle of an expanding rubber gasket, but often features a wing-nut style handle instead of a T-handle. For some people, this design offers a slightly better grip, especially if you’re working in a tight compartment where a T-handle might hit the sides.

Installation is identical to the Camco: drain the tank, insert the plug, and hand-tighten the wing nut. The seal is reliable for the low-pressure demands of a water heater, and the lack of threads means you can’t cross-thread or damage the tank’s drain fitting. This is a huge benefit, as repairing a damaged water heater fitting is a major headache.

Choosing between the Valterra and the Camco often comes down to brand preference or which handle style you find more ergonomic. Both are excellent, purpose-built solutions that dramatically simplify a common RV maintenance task. They are designed to be installed and removed frequently, making them perfect for active RVers.

Dorman AutoGrade Plug: Most Durable Construction

When you need a plug that’s more of a permanent fixture, the Dorman AutoGrade line is where you should look. Coming from the automotive world, these plugs are built for durability. They typically feature a brass or steel construction with a high-quality neoprene rubber gasket that resists breakdown from chemicals and temperature changes.

Unlike the tool-free RV-specific plugs, a Dorman plug requires a wrench to tighten the nut that expands the rubber. This is its key tradeoff. You lose the convenience of hand-tightening, but you gain a much more robust and secure seal that can withstand more vibration and pressure. It’s a "set it and forget it" solution.

This is the right choice for a drain you don’t access often, or if your factory plug has failed and you want a rock-solid, semi-permanent replacement. It’s also a great option for other applications around your rig, like plugging a leaky fitting on a freshwater tank until you can perform a proper repair. Just be sure to measure the inner diameter of the pipe you need to plug.

Oatey Gripper Plug: Superior Mechanical Seal

Oatey is a name plumbers trust, and their Gripper mechanical plugs show why. These are heavy-duty tools designed for sealing pipes for pressure testing, which means they create an incredibly strong seal. The large plastic wing nut provides significant mechanical advantage, allowing you to compress the thick rubber gasket with immense force.

For an RV water heater drain, the Oatey Gripper is frankly overkill. However, its strength makes it an invaluable addition to your RV emergency toolkit. Imagine you’re on the road and a P-trap under a sink cracks. You can remove the broken trap and use a Gripper plug to seal the pipe from the holding tank, preventing odors and spills until you can get to a hardware store.

This plug is a problem-solver. It’s not the most convenient option for a frequently used drain, but for creating a temporary, watertight seal on almost any open pipe, it has no equal. Its ability to hold against pressure gives you options for repairs that simpler plugs just can’t offer.

Koehler Brass Lever Plug for Long-Term Use

The Koehler brass lever plug offers a brilliant combination of durability and convenience. Instead of a screw mechanism, it uses a cam lever. You simply insert the plug and flip the lever down, which expands the rubber gasket to create a tight, secure seal. It’s the fastest and easiest to operate of all the durable metal plugs.

Constructed from solid brass, this plug is built to last a lifetime. It won’t rust or corrode, and the simple mechanical action is incredibly reliable. This makes it a fantastic permanent upgrade for any drain you need to access regularly, not just your water heater. Think freshwater tank drains or even livewell plugs on a boat.

The primary tradeoff is cost; these are typically more expensive than other options. But if you value speed and want a premium, buy-it-for-life solution that requires no tools and operates in a fraction of a second, the Koehler lever plug is an investment in convenience that pays off every time you use it.

LASCO Rubber Test Plug: Best Value Multi-Pack

Sometimes you just need a simple, effective plug without the frills. The LASCO rubber test plug is a basic, no-nonsense tool that gets the job done. It consists of a simple rubber stopper, two metal or plastic washers, and a wing nut. It’s the classic design and it works.

The biggest advantage here is value. You can often buy these in multi-packs with several different sizes for the price of one premium plug. Having an assortment of these in your RV toolkit is a smart move. You never know when you’ll need to temporarily cap a line, and having the right size on hand can save a trip to the store.

While the materials may not be as robust as a Dorman or Koehler, they are more than adequate for temporary fixes or low-stress applications. For the RVer who likes to be prepared for anything, a multi-pack of LASCO plugs is cheap insurance against a wide range of potential plumbing issues.

Installing Your Camco or Valterra Drain Plug

Switching to a tool-free plug is one of the quickest RV upgrades you can do. The process is the same for both the Camco and Valterra models and takes less than five minutes.

First, and most importantly, make sure the water heater is turned off and the water has had time to cool down. Open a hot water faucet inside your RV to relieve any pressure in the system. Once the pressure is gone and the water is cool, you can head outside to the water heater compartment.

Use a wrench to remove the old plastic plug. A little water will drain out, which is normal. Once it’s out, simply insert your new Camco or Valterra plug into the opening. Turn the handle or wing nut clockwise by hand. You only need to tighten it until it feels snug; the goal is to expand the rubber just enough to create a seal. Do not over-tighten, as this can damage the plug. That’s it—you’re done.

Sizing Plugs from Dorman, Oatey, and LASCO

While the Camco and Valterra plugs are purpose-built for the standard 1/2" NPT drain on most RV water heaters, the more generic plugs require you to do a little homework. Plugs from Dorman, Oatey, and LASCO are sold based on the pipe size they fit, and getting it wrong means you won’t get a seal.

Before you buy, you must measure the inside diameter (ID) of the pipe or fitting you need to plug. Don’t guess. A cheap pair of digital calipers is an invaluable tool for any RVer, and this is a perfect use for them. Measure the opening, write it down, and take it with you to the store or look it up online.

These plugs are designed to fit a specific range. For example, a "1-1/2 Inch" plug might be designed to seal pipes with an ID from 1.4 inches to 1.6 inches. The packaging will always state the working range. Taking a moment to measure first ensures you buy the right plug the first time, avoiding the frustration of a leaky seal.

That cheap plastic plug that came with your RV is a failure point waiting to happen. For a few dollars and a few minutes of your time, you can replace it with an expandable plug that eliminates tools, stripped threads, and frustration. It’s a small detail, but mastering the small details is what makes small living work so well.