Short answer: not on its own
Untreated vegetable-tanned leather is not waterproof. It soaks up water quickly and darkens where it is wet. A little water does not usually cause lasting harm, but repeated soaking and drying can dry out the leather, stiffen it and eventually crack it. Vegetable-tanned leather can be made water-resistant. A full waterproof seal is not really achievable without changing its feel.
Chrome-tanned leather is not waterproof either. How to identify chrome tanned leather can help you tell which tannage you have.
Why vegetable-tanned leather takes up water
Vegetable tanning uses plant tannins to stabilise the hide. The result is an open, absorbent structure that takes dye, wax and oil well. The same openness lets water in.
This is also why leatherworkers dampen vegetable-tanned leather before they tool it or wet-mould it. Types of leather explained covers how the tannage affects the rest of the leather’s behaviour.
What happens when it gets wet
- It darkens, sometimes unevenly.
- Water spots form if only part of the surface gets wet, because the edge of the wet area dries differently.
- Heat causes shrinkage. Wet vegetable-tanned leather has a shrinkage temperature of only about 70 to 85 C, well below that of dry leather. Hot, wet vegetable tan can shrink and harden, which is the principle behind hardening leather by baking.
- Repeated soaking washes out oils. The leather can become stiff and eventually crack.
Handling water spots
Water spots are often fixable if the leather is not damaged:
- Dampen the whole affected panel evenly, working from the spot outward, so the edge of the wet area is not visible.
- Dry slowly at room temperature, away from heaters and sunlight.
- Once dry, recondition lightly to replace lost oils.
Test on a hidden area first, because even careful dampening can change the colour.
Drying wet leather the right way
- Dry at room temperature, away from radiators, heaters and direct sun.
- Stuff the shape with paper, such as newspaper, so it keeps its form as it dries.
- Do not use a hairdryer or heater. The heat causes shrinkage and cracking.
- Recondition lightly once the leather is fully dry.
Water-resistance options
Several approaches add water resistance:
- Beeswax-based dressings, which give a light layer that keeps some breathability.
- Hot-stuffing with waxes and oils, a process usually done in a tannery or with care in a workshop.
- Oils, such as neatsfoot oil, which soften the leather and add some resistance but can darken it.
- Acrylic top coats, such as Resolene, which seal the surface more fully. Leather finishing covers how sealers fit into the finishing order.
- Wax-acrylic blends, which combine features of both.
Each option has trade-offs. Waxed vs oiled leather explains how waxes and oils differ in feel and in the water protection they give.
Trade-offs: breathability and patina
Leather breathes, and full waterproofing would stop that. Top coats and heavy waxes also slow the natural patina that makes vegetable-tanned leather appealing.
Choose the level of protection that suits the item. A lightly dressed belt and a heavily sealed outdoor bag will look and behave differently. How to choose leather for a project helps match the protection to the job.
Waxed vegetable-tanned leathers
Heavily stuffed and waxed vegetable-tanned leathers, such as bridle and harness leather, resist water better than plain vegetable tan. The treatment is part of how they are made. They are still not waterproof, and they still need upkeep.
Salt water, mould and storage
- Salt water leaves white tide marks. Rinse with clean water and dry slowly.
- Damp storage can lead to mould. A common guideline is to keep storage below about 60% relative humidity.
Safety note
Never put wet leather near open flames, heaters or ovens to dry. The heat can scorch the leather and shrink it.