Columbia offers a comprehensive line of water repellent and waterproof jackets that come with limited lifetime warranties. Columbia's Omni-Shield waterproofing technology offers comfort and breathable material with excellent water resistance. If your jacket stops repelling water, you can treat the fabric to repel it again.
Clean your jacket thoroughly. Depending on the level of soil, you can wipe down your jacket with a damp cloth or throw it in the washing machine.
Spray down the exterior shell of the jacket with waterproofing spray. Don't be afraid to use too much. Make sure all parts of the jacket and the seams are covered.
Tumble dry the jacket on high heat after using the spray. This makes the spray adhere to the surface of the coat and form a protective layer. Most sprays require drying for a prescribed length of time.