Is it safe to go through a car wash with a tonneau cover?

The makers' own instructions agree on the basics. Agri-Cover's LOMAX manual says to keep the cover closed and latched in automatic car washes and warns that a pressure washer held too close can damage paint, hinges or seals. Peragon says to lock the cover before a car wash because the blowers can push it open. TruXedo's Lo Pro QT manual says the vinyl can go through a car wash if the soap is rinsed off. A 2021 etrailer answer relays BAK's position: a car wash is fine if the cover is closed and secure, but avoid brush washes, which can abrade the cover and hit the clamps hard enough to dislodge the rail.

RealTruck, which owns BAK, Retrax, UnderCover, Extang and TruXedo, breaks it down by type in a blog updated in April 2026. Touchless and hand washing are the safe options; brush and roller washes are the most likely to cause damage. Soft roll-ups can flap and stretch under brushes, which strains the mounting. Soft tri-folds can let water through the panel seams under high pressure. Hard folders and one-piece lids generally cope, though brushes can scratch them. High-pressure spray and brushes can damage a hard roll-up's seals and finish, and water can get into a retractable's canister. This is a manufacturer's guidance, not testing; no independent car-wash test was found.

The bed will probably get wet. Every cover leaks to some degree, and Retrax, Roll-N-Lock, Pace Edwards and Worksport exclude water from their warranties. In a September 2026 Reddit thread, a dealer-installed BAKFlip MX4 left standing water in the bed after a car wash, and the owner said BAK called the leaking normal. Retrax adds a maintenance point: rail weather-stripping can absorb car-wash soap, so wipe the inside of the rails now and then, and never spray cleaner or lubricant into them, which voids its warranty.