How to Waterproof a Laptop Bag for Rainy Days

By Rains® | Explore Waterproof Jackets, Bags & Outerwear | Published: 2026-10-25

Category: How-to Guides

Keep your laptop dry with these practical steps to waterproof any laptop bag, including tips for canvas bags and caring for waterproof coatings.

Quick answer

To waterproof a laptop bag for rainy days, start by checking if the bag already has a waterproof coating, then apply a fabric waterproofing spray evenly, paying special attention to seams and zippers. Let it dry fully before use.

Why waterproofing matters for your laptop bag

A wet laptop bag doesn't just mean a damp shoulder — moisture can seep through fabric and damage your electronics. Even bags labeled water-resistant may fail in a downpour if the coating has worn off or seams aren't sealed. Taking a few minutes to treat your bag gives you real rain protection for your laptop bag, whether you commute daily or travel occasionally.

Canvas vs. synthetic bags: what to expect

Canvas bags are naturally absorbent, so they need a heavier-duty waterproofing spray designed for natural fibers. Synthetic bags (nylon, polyester) often come with a DWR (durable water repellent) finish that can be revived with a tech wash or spray. If your bag already has a waterproof membrane — like the Rains Laptop Bag 13″/14″ — you mainly need to maintain the coating and keep zippers clean, not apply a new treatment.

Steps to waterproof your laptop bag

1. Clean the bag thoroughly: Remove all contents and brush off loose dirt. Wipe down the exterior with a damp cloth and mild soap. Let it dry completely — any moisture trapped under the spray will reduce effectiveness. A common mistake is applying spray to a dirty bag; dirt blocks the coating from bonding to the fabric.
2. Choose the right waterproofing spray: For canvas bags, pick a heavy-duty fabric spray. For synthetic bags, use a DWR restorer or all-purpose waterproofing spray. Avoid silicone-based sprays on breathable fabrics. Check the label to ensure the spray is safe for your bag's material — some sprays can discolor certain fabrics.
3. Apply the spray evenly: Hold the can 6–8 inches from the bag and spray in a sweeping motion, covering the entire exterior. Pay extra attention to seams, zippers, and the bottom panel. Apply two thin coats rather than one thick coat. Over-saturating can leave sticky residue or stiff fabric; light, even coats work best.
4. Let it cure fully: Hang the bag in a well-ventilated area away from direct sunlight. Allow 24 hours for the coating to cure before using the bag or adding any items inside. Rushing this step is the most common mistake — a partially cured coating can wash off in the first rain.
5. Test and reapply as needed: Sprinkle a few drops of water on the treated surface. If water beads up and rolls off, the coating is working. If it soaks in, apply another coat. Reapply every 3–6 months or after washing the bag. Don't wait for a rainy day to test — do it in the sink so you know your laptop bag rain protection is solid.

Product spotlight

Laptop Bag 13″/14″: The Rains Laptop Bag 13″/14″ is a waterproof bag with a main compartment and an external pocket that fits a 13″ laptop. If you own this bag, you already have built-in rain protection for your laptop bag; focus on maintaining the coating and keeping zippers free of debris rather than applying a new waterproofing treatment.
Laptop Bag 13″/14″