TL;DR
Get the fur out before the cover goes anywhere near water, because wet fur mats into the fabric and clogs a machine filter. Shake it, vacuum it, then wash cool with unscented detergent and no fabric softener, which would destroy the waterproof backing. Air dry it flat and refit every anchor and strap properly.
Why fabric softener is the main mistake
Most dog car seat covers have a waterproof or water-resistant backing, and that is the whole point of the product. Softener coats it, and a coated backing lets liquid soak through to your car seat instead of holding it on the surface.
Softener also leaves a slick film on the top surface, which reduces the grip that keeps a dog from sliding around on a corner.
Heat is the second mistake. A hot dryer can delaminate or crack a waterproof backing, melt the non-slip coating, and shrink the cover so the anchor straps no longer reach.
So the rule is cool wash, unscented detergent, no softener, and air dry. Everything else is detail.
How do you wash a dog car seat cover?
Take the cover out, shake it outside, and vacuum both sides thoroughly. Pre-treat any stains, then wash it on a cool gentle cycle with a small amount of unscented detergent and no fabric softener. Add an extra rinse, then hang or lay it flat to air dry completely.
The step-by-step routine
1. Remove it from the car and shake it outdoors. More comes out than you expect.
2. Vacuum both sides. Do the top face, the underside, and every seam and pocket. A crevice tool along the seat crease line where the cover folds.
3. Dry brush the fur. A rubber brush or a pet hair tool over the top surface. Wet fur mats into fabric and clogs a machine filter, so this step is not optional.
4. Pre-treat stains and greasy spots. Work a drop of unscented detergent in with your fingers and leave it fifteen minutes.
5. Treat urine and vomit with an enzyme cleaner first. Blot, rinse with plain water, apply the product, and let it stay wet for the time the label says. Enzymes break down the compounds causing the odor rather than masking them.
6. Close every fastening. Hook-and-loop strips grab everything in a drum, and open buckles bang around.
7. Wash cool on a gentle cycle. A small amount of unscented detergent. Never fabric softener, and never chlorine bleach.
8. Add a second rinse. Detergent residue in a waterproof fabric acts as a wetting agent, which is the opposite of what you want.
9. Air dry flat or over a rail. Out of direct sun. A large quilted cover can take a full day.
Very large covers may not fit a home machine. In that case, hand wash in a bathtub with warm water and unscented soap, press rather than wring, rinse several times, and dry it flat.
Straps, anchors and the parts that hold it up
Hammock-style covers hang from the headrests, and those straps carry the load.
Wipe the straps and buckles with warm soapy water and a brush, then wipe the soap off and dry them. Do not bleach or solvent-clean webbing, since both weaken the fibers, and do not soak plastic buckles in hot water.
Check the stitching where each strap meets the cover. Bar-tack stitching that is fraying is the point that fails, and a strap that gives way drops the hammock and the dog with it.
Clean the seat anchors and the tuck-in flaps too, since they collect crumbs and grit that end up back on the clean cover.
The manufacturer's instructions govern fitting and any load-bearing part, so follow the label for your specific cover. A dog car seat cover is a surface protector, and it is a separate question from restraint. If you want your dog secured while traveling, ask your veterinarian or a trainer what suits your dog and vehicle rather than treating a hammock as a restraint.
Source: American Veterinary Medical Association pet travel safety guidance
Getting the smell out
Car interiors bake in the sun, which concentrates odor in anything left in them.
Wash with an enzyme-based laundry product for anything organic. Soak the cover for an hour in cool water with the product, then wash cool and rinse twice.
Baking soda sprinkled on a dry cover, left fifteen minutes and vacuumed off, handles light odor between washes.
Chlorine bleach is off the table. It destroys waterproof backings and weakens fabric, and it must never be combined with ammonia, which is present in urine, or with vinegar or any acid, since those release chloramine and chlorine gas.
Scented sprays are also worth avoiding. A car is a small enclosed space, dogs have a far more sensitive nose than people, and a strongly scented cover can make travel less comfortable rather than more.
If the smell persists after a proper wash and dry, check the seat underneath. Liquid that got past the cover soaks into car upholstery, and that is a different job that usually needs an extraction machine or a professional.
Fitting it back correctly
A cover that fits badly bunches, slides, and stops protecting the seat.
Hook the headrest straps first, adjust them so the hammock hangs level, then tuck the side flaps deep into the seat crease. Fasten the seat anchors, and check that seat belt access and any child seat anchor points are not blocked or obstructed.
Do not cover an airbag or block any airbag deployment area. If your vehicle has side airbags in the seat backs, check your vehicle manual before fitting anything against them.
Smooth the cover flat and check that nothing bunches under where the dog sits, since a fold under a paw becomes a slip.
How often should you clean it?
Vacuum it weekly if your dog rides often, and wash it every two to four weeks. Wash immediately after mud, a beach trip, road salt, or any accident, since salt and sand are abrasive and salt corrodes hardware.
Keeping two covers means one can dry properly while the other is in the car, which is the same logic that makes two harnesses or two crate trays worthwhile.
Travel gear is easiest to clean as a batch. Strollers have a wheel and axle problem of their own, covered in how to clean a pet stroller, and carriers hold odor in their padding, covered in how to clean a soft or hard pet carrier.
For bowls, beds and the rest of the kit, our guide to cleaning pet bowls, bedding, toys and gear uses the same wash-cool and dry-fully rules.
FAQ
Can you machine wash a dog car seat cover?
Most can, on a cool gentle cycle with a small amount of unscented detergent and no fabric softener. Shake and vacuum the fur off first, close all fastenings, and add an extra rinse. Air dry it flat rather than using a machine dryer, which damages waterproof backings.
Why should you not use fabric softener on a dog car seat cover?
Softener coats the waterproof backing so liquid soaks through to the car seat instead of staying on the surface, and it leaves a slick film that reduces grip. Skip it entirely and add a second rinse instead, since detergent residue causes a similar problem.
How do you get dog hair out of a car seat cover?
Shake it outdoors, then vacuum both sides with a crevice tool along every seam, and finish with a rubber brush or pet hair tool over the top surface. Do all of this before washing, because wet fur mats into the fabric and clogs the machine filter.
How do you get the smell out of a dog car seat cover?
Soak it for an hour in cool water with an enzyme-based laundry product, then wash cool and rinse twice. If the smell persists after a proper wash and dry, liquid has probably reached the car seat underneath, which needs its own treatment rather than another cover wash.
Can you put a dog car seat cover in the dryer?
Avoid it. Machine heat can delaminate or crack a waterproof backing, melt non-slip coatings, and shrink the cover so the anchor straps no longer reach the headrests. Hang it or lay it flat to air dry instead, allowing a full day for a large quilted cover.
How often should you wash a dog car seat cover?
Vacuum weekly if your dog rides often and wash every two to four weeks. Wash immediately after mud, a beach trip, road salt, or any accident. Road salt and sand are abrasive and salt corrodes hardware, so neither should be left to dry in the fabric.
Travel gear is a small part of a much larger job. Every home is different, so the real number depends on size, condition, and what you want covered. Get a quote or read more about house cleaning services.