Pickup truck owners know that an open truck bed leaves their cargo exposed to the elements. Driving in the rain or through puddles can easily soak your gear. A good tonneau cover provides a practical solution to keep your truck bed and cargo dry. But will a tonneau cover really protect your cargo from getting wet?
How Effective Are Tonneau Covers At Keeping Out Water?
A tonneau cover will provide significant protection against rain and water for your truck bed. However, most tonneau covers are not 100% waterproof or watertight. The level of water protection offered depends on the specific cover.
Water-Resistant Design
Tonneau covers are designed to be water-resistant. The durable vinyl, canvas, or aluminum construction repels water from the top surface. This prevents rain and other precipitation from freely entering the truck bed from above.
Well-fitted tonneau covers with tight seams will deflect the majority of standing water on the surface. This water-resistant barrier makes tonneau covers far more effective at keeping truck beds dry compared to an open pickup.
Minimal Water Intrusion
While not completely watertight, a properly installed tonneau cover will minimize water intrusion. Only a small amount of moisture may seep in around the edges during heavy rain or when driving through deep puddles.
For light to moderate rain, a tonneau cover will keep the truck bed essentially dry. The cargo area should stay protected against dampness.
Surface Runoff Control
By covering the truck bed, tonneau covers prevent uncontrolled water runoff from entering. Rain or exterior wash water can’t directly pour in from above. This enables much greater control over moisture levels in the cargo area.
Condensation Prevention
Tonneau covers create a protective barrier between the truck bed and the outside environment. This barrier helps prevent condensation from building up on tools or cargo inside the truck bed.
How Much Water Protection Do Different Tonneau Covers Provide?
The amount of water protection a tonneau cover provides depends on the material and design:
Soft Vinyl Covers
Basic soft vinyl tonneau covers offer good water resistance from precipitation and surface runoff. However, the vinyl material and snap connections may allow notable water intrusion, especially around the tailgate.
Canvas Covers
Canvas tonneau covers treated with water-resistant coatings provide enhanced protection. The fabric repels water while still allowing easy roll-up access. Leaks are minimized but still possible over time as the material wears.
Folding Covers
Folding panels made with vinyl-coated aluminum or polymer provide better water protection. When closed, the hinged panels seal tightly to deflect standing water. Minimal leakage may occur at panel joints.
Retractable Covers
Retractable tonneau covers almost completely seal the bed to prevent water entry. The rigid vinyl-coated aluminum panels lock together and mount tightly against the bed rails when closed. However, the retractable slats may leak slightly.
Hard Lids
Hard plastic or aluminum tonneau lids offer the most waterproof protection. When mounted and sealed correctly, essentially no water can enter the bed. Hard lids form an impermeable moisture barrier.
Can Tonneau Covers Get Completely Soaked In Heavy Rain?
In extremely heavy rain, tonneau covers may get completely soaked. However, well-designed covers will still provide substantial water protection for the truck bed:
Water Stays on Surface
The water-resistant tonneau cover surface prevents rain from freely soaking into the material. Much of the moisture beads on top without penetration. This protects cargo underneath.
Cover Prevents Ponding
Tonneau covers stop uncontrolled water ponding in truck beds. Without a cover, heavy rain can quickly fill an open truck bed and soak cargo. The cover contains runoff.
Durable Materials Resist Soaking
Quality tonneau covers use vinyl, aluminum and other heavy-duty materials. These materials are engineered to withstand being soaked and prevent moisture transmission.
Tight Seal Around Perimeter
A snug, tight fit around the bed sides, tailgate, and corners is key. This gasket-like seal deflects overflowing water off the cover edges. Minimal seepage may occur at attachment points.
Drainage Vents
Some tonneau covers have built-in drainage vents. These pressure relief valves allow excess pooled water to drain off without compromising the cover’s protection when closed.
Can I Drive Through Deep Puddles Without Getting My Cargo Wet?
Driving through deep puddles can be a challenge for tonneau covers. The impact and weight of high volumes of water may lead to some leakage:
Momentary Spray Possible
Hitting deep puddles causes water to splash up under tonneau covers. This can spray a bit of moisture onto cargo before draining out.
Seepage Around Edges
Tonneau covers are not watertight seals. Large puddles can leak small amounts of water in around cover attachments and side rails.
Drainage Vents May Inundate
Excessive water volumes from puddles may overflow through tonneau cover drainage vents meant for lighter runoff. This can briefly flood truck beds.
Soft Covers More Vulnerable
Vinyl and canvas soft covers are most prone to puddle leaks. Hard folding or retractable covers withstand puddle impacts better and resist edge seepage.
Minimal With Correct Installation
Properly installed tonneau covers tightened to the bed will significantly limit puddle leakage. Gaps and poor alignments allow excess moisture to infiltrate.
How Can I Make My Tonneau Cover More Waterproof?
If your current tonneau cover allows more water into the truck bed than desired, there are ways to improve its water protection:
Inspect/Reseal Edges
Make sure the cover edge seals and gaskets are intact and snugly fitted. Reseal with caulk or foam if any gaps or cracks are found.
Add Protective Coating
Applying a truck bed spray liner coating on the underside of a soft vinyl cover enhances water resistance. This creates a more impermeable water barrier.
Install Drain Tubes
Adding drain tubes helps remove any moisture that gets under the cover, keeping your cargo dry. Drain tubes route water out through the front or back of the bed.
Upgrade Cover
Switching to a multi-panel retractable cover or hardshell lid provides maximum waterproofing. Their rigid materials and tight seals outperform soft covers.
Use Bedliner
Applying a spray-in bedliner beneath the tonneau cover helps protect against moisture. The textured material minimizes leaks through the truck bed floor.
Improve Sealing
Add rubber sealing strips on the underside edges of the cover to block moisture flow. Adjust the clamps or side rail mounts to compress the seals tighter.
Should I Get A Waterproof Tonneau Cover?
If you need to keep cargo fully dry in all conditions, choosing a waterproof tonneau cover is a smart option:
Maximum Rain Protection
Waterproof tonneau covers prevent virtually any water from touching your cargo, even in torrential downpours or storms.
No Leaks Through Seals
Waterproof covers utilize rubber gaskets and multiple secure sealing points to eliminate gaps where water can intrude.
Withstand Puddle Splashes
Waterproof covers are engineered to withstand wave impacts and resist bed flooding when hitting deep puddles at speed.
Specialized For Boats/Motors
Some waterproof covers are designed specifically to keep expensive boats or motors fully dry and undamaged during transport.
Allow Cargo Washing
You can safely wash dirty cargo or muddy gear inside the bed without worrying about moisture soaking in.
Added Cost
Waterproof covers typically cost more than regular vinyl or canvas covers. But for critical moisture protection, they are worth the investment.
Limited Style Selection
Far fewer waterproof cover styles and colors are available. But form follows function when ultimate water protection is needed.
The Bottom Line
While tonneau covers may not completely waterproof your truck bed, they will provide valuable protection against rain, splashes, and runoff. Hardcovers and retractable tonneaus deliver the most water protection.
Waterproof-specific covers ensure zero moisture reaches cargo. With the right tonneau cover installed, you can transport equipment confidently knowing splashes and downpours won’t saturate the truck bed interior.