Most Waterproof Tonneau Cover: The Sentry CT, and Why None Is Sealed

Shop for a waterproof tonneau cover and you'll find covers marketed as leakproof. None of the covers we've reviewed earns the word. Every design has gaps to close with rubber and foam: at the cab, at the tailgate, along the rails and, on most styles, across the bed where panels fold or slats meet. Some close them far better than others, and that difference is what this ranking measures.

We rank every cover we've reviewed on two things from its review: our leak-risk gauge, which rates a cover as it arrives, and the water record behind it, including where the water gets in. The gauge stays blank when the reports are too thin to set it, so a blank is a short record, not a bad mark.

Set the bar before you read on. A dry cover, in this guide, means a few drops at most after a storm or a wash. If a drop on your cargo is a problem, no cover fixes that alone; the bone-dry section near the end is for you.

The water ranking: every cover we have reviewed

Driest first. The gauge is each review's reading, and the record and leak points restate what that review found.

Read the blanks with care. The X4s sits second without a reading because its record points the same way as the CT's on fewer, newer covers; our comparison of the two gives the CT the edge on a deeper record and less install fuss. The T3 and the F1 sit where their short records put them, and a few more reports could move either one.

Neighboring rows are often ties. The LEER and the Ultra Flex are level, and the Low Profile matches them only when its rails are square. The PRO XR and the Peragon are both close calls between moderate and high. The Lo Pro and the RetraxONE XR tie near the bottom: every report on either one describes water.

The MX4 sits last because most of its water reports describe leaks on the cover as it arrives, at the front corners first. Sealing work explains the spread between its owners. An MX4 sealed all round with black silicone gets to about 98 percent and still lets a little in during hard rain, an older MX4 has gone eight years without leaking much, and on a Tundra the MX4 that replaced a leaking factory cover left the bed soaked after every rain and ruined some cargo. Our gauge reads the cover before anyone seals it, and we'd rather buy one that doesn't need the work.

Where each style lets water in

A cover leaks at its joints, and each style puts them in different places.

• Hard roll-ups: the Sentry CT and the X4s each carry one continuous top over aluminum slats, so no seam crosses the bed. What's left is the perimeter: the rear edge where it meets the tailgate, and the front corners, where a cover that rides up leaves a gap. The X4s has no drain tubes in its parts list.
• Hard folders: every hinge is a seam across the bed, sealed rubber to rubber. Add the front corners at the cab, the tailgate end and the side rails. Flush folders such as the MX4 sit level with the bed rails, catch rain on top and carry it along the rails to drain tubes at the cab end, so a tube that slips off empties into the bed.
• Retractables: slats ride in side tracks, and water that gets under the top runs along them. Those rails are the RetraxPRO XR's main leak path, the tailgate seam comes next, and the RetraxONE XR adds the canister end. The Peragon folds its panels into the bed instead of a canister, so its weak points are the rubber between panels and along the edges, which lets in more as it ages.
• Soft roll-ups and tri-folds: vinyl sheds water only while it's tight. Slack vinyl sags, holds a puddle and feeds it to the corners, and a tri-fold's folds are extra seams. The Lo Pro's hook-and-loop seal along the rails is only as good as the tension you keep on it.
• One-piece lids: a single lid has no seam across the bed. We haven't reviewed one, so none is ranked here; more in the bone-dry section.

Count the seams and you'd expect the folders with the fewest panels to stay driest. A tri-fold has three panels and two hinges; a quad-fold like the LEER has four panels and three hinges. Yet the LEER sits with the driest folders, and the three-panel Ultra Flex sits level with it rather than ahead. How a cover seals its joints matters more than how many it has.

The tailgate is a leak point on every style. A closed gate doesn't seal itself to the bed, so a cover can only do so much at the back; the seal kits under setup below are what close it.

What the makers promise, and what they leave out

The makers' install sheets are more careful with the word waterproof than their marketing is.

• BAK: the install sheet for its BAKFlip folders and its Revolver sheet, which covers the X4s, both say the cover is not airtight and that keeping cargo clean and dry takes special care.
• RealTruck: the Sentry CT's Amazon listing and RealTruck's X4s page both call those covers the most leakproof of all folding, roll-up and retractable designs. That's a marketing comparison, and BAK's own install sheet for the X4s still says the cover is not airtight. The CT tops our ranking on owner reports, not on that line.
• Peragon: its FAQ says water seeps in along the sides and around the tailgate on any retractable, and that a cover left in steady rain for a long stretch will leak.
• Rough Country: no waterproof claim for the Low Profile, no named perimeter seal on its product page, and an in-box warranty that excludes weather-related damage.
• Tyger: no waterproof claim for the T3. It ships a seal strip for the bulkhead, the tailgate and any gap between the bed and the cover.

Put those together and the most any maker will stand behind is a mostly dry bed. Judge a cover by how close to dry it gets and how mild its misses are, and treat "leakproof" on a listing as a sales word.

The four driest covers we would buy

Our picks, from their makers' pages, with each review's leak-risk reading:

All four clamp on without drilling on most trucks, per their makers, and none publishes a cover weight. None of those ratings is for standing on: each assumes the weight is spread across the whole closed cover.

• TruXedo Sentry CT: the driest cover we've reviewed. Its one-piece canvas top over slats leaves nothing to fold, and its misses are mild. Shut the tailgate first and the cover second, since the CT's rear seal sits on top of the gate, and on a 3rd gen Tacoma check that the rail lies flat at the tailgate end before you trust it in rain.
• BAK Revolver X4s: the same roll-up idea under a vinyl top, with no drain tubes to look after. Its record reads dry on a handful of mostly new covers, which is why our gauge is blank. It costs more than the CT on most matching listings, seating it takes patience, and RealTruck says its 5 ft 7 in Ram part won't work with the multifunction tailgate.
• UnderCover Ultra Flex: the folder we'd buy for a dry bed. Its misses don't cluster in one spot, so there's no known weak point to chase, and the folded stack stands off the rear glass on prop rods. It cost a little less than the CT on every matching listing we compared.
• LEER HF650M: the cheapest of the four and the one folder here with no drain tubes. Nobody reports a wet bed under one, though the record is short. It won't fit a RamBox or a Ram multifunction tailgate, the warranty runs 3 years, and LEER no longer lists it on its own site.

On a 4th gen Tacoma, a 2024-on Ranger or a 2023-on Colorado or Canyon, we haven't matched a Sentry CT listing on Amazon, though RealTruck lists the CT for all three. Search for the 4th gen Tacoma CT, the Ranger CT or the Colorado and Canyon CT and check fit for your truck. The X4s and the Ultra Flex have confirmed listings for the 4th gen Tacoma and the Colorado, and the LEER for the 4th gen Tacoma and the Ranger. Our Sentry CT against the X4s comparison goes deeper on the two roll-ups.

Setup decides how dry yours stays

A well-sealed cover installed carelessly leaks like a poor one. These are the setup steps that move a bed from damp to dry on the covers we've reviewed:

• The cab end: on many folders the front corners leak first. Make sure the cover's front seal overlaps the bulkhead foam across the full width, and clean the front wall of the bed before anything adhesive goes on it, above all over a spray-in liner, where one F1's seal came unstuck after a wash. LEER packs a packet of putty for the bed seam near the cab; on a Maverick that seam sits about 6 in behind the cab.
• The tailgate: a tailgate seal kit is the usual cure for water at the back. Take care at the corners, because a kit that leaves openings can do harm: one Sentry CT took more water in car washes after its owner fitted one.
• Square and flush: rails that aren't square leave gaps the seals can't reach, and the Rough Country Low Profile runs dry or wet largely on this. On the X4s, a rear edge that won't sit flush often means the cover sits too far forward, and its four hand nuts let you slide it back.
• Drain tubes: on covers that use them, route each tube out of the bed and check the ends after the first few storms. The LEER and the X4s have none to check.
• Soft covers: keep the vinyl tight and press the hook-and-loop down along both rails, then check it again after a few weeks.

Before you trust the bed with anything, wet the closed cover with a garden hose a section at a time, opening it after each section to find any water. Work from outside: never get into the bed with the cover shut, and BAK's Revolver sheet says that cover has no release from inside the bed. Our leaking tonneau cover fixes walk through each leak point, and the drain tube guide covers routing and drilling truck by truck.

Car washes

A wash bay tests a cover differently from a storm. Rain lands from above; a wash fires pressurized water at the tailgate gap, and the dryers at the exit push what's left on the top sideways into the seams. Our picks show where that lands. Half the Sentry CT's misses are car-wash drips at the tailgate end, the Ultra Flex has both a dry wash report and a wet one at the tailgate, and the LEER's worst wash report is a few trickles. We'd pick a touchless wash for any cover, and Tyger recommends only touchless washes for its vinyl covers. Our car wash guide has each maker's care rules.

When the cargo has to stay bone dry

Then no tonneau cover is the whole answer. Here's what we'd do:

• Sealed bins: a gasketed tote under any good cover keeps a drip off whatever's inside it. Load the middle of the bed rather than the ends, where most covers let their water in.
• A camper shell: it roofs the entire bed and shuts with a door of its own, and owners who make the move report a much drier bed. Sealed it isn't. Dust still finds a way in, and tire spray on a flooded road can push water up through the bed's drain holes, so keep the bins. Our tonneau cover vs camper shell guide weighs the trade in bed access and height.
• A one-piece lid: some of the strongest dry claims come from owners of one-piece lids, a style we haven't reviewed. An owner hauling sensitive electronic test equipment chose an UnderCover SE and calls it completely waterproof, and another calls an UnderCover one-piece ABS lid water tight. Those are owners' words on covers we haven't reviewed, not our rating, so neither lid is ranked here. The trade is bed access: a one-piece lid doesn't fold or roll out of the way, and the SE owner gets into the bed by the tailgate step.

If you only need a dry bed now and then, a cover from the top of our ranking plus a couple of sealed bins does the job and keeps the bed open for tall loads. We haven't priced shells, so get a quote for your truck before you weigh the cost.

The cover we would put on a truck that has to stay dry

Buy the TruXedo Sentry CT. No cover we've reviewed has a better water record, its misses are drips rather than puddles, and it rolls clear of the rear window when you need the whole bed. If you'd rather have a vinyl top, the X4s is the nearest match on thinner evidence. If you want a folder, take the Ultra Flex, or the LEER for less money and no drain tubes. If a dry bed is the reason you're shopping, skip the MX4.

Already own a cover that leaks? Work through our leaking tonneau cover fixes before you replace it. Still choosing a style? Our hard vs soft guide covers what each one costs you beyond water.