If you are frequently exposed to rainy weather, you might want to make your jeans waterproof to keep feeling dry and comfortable. A wash-in waterproof solution will waterproof your jeans as you wash them. Durable water repellents, or DWRs, won't damage your clothes or make them stiff. Rather, they bond with the fibres of your clothing to protect the fabric. DWRs are used to help make raincoats and other gear waterproof and are available at camping or outdoor supply stores.
Place your clean pair of jeans in the washing machine.
Insert the water repellent wash-in product into the machine dispenser where the detergent usually goes. Follow the instructions on the label for how much product you should use.
Run your washing machine through a normal wash cycle.
Allow the item to drip or tumble dry. It is now ready for wear. Reapply repellent as needed after multiple washings.
You also can wash the jeans by hand in the solution and allow them to air dry for the same waterproofing effect. The waterproof solution must be applied after the jeans have been washed in regular detergent.