We consider a truly waterproof jacket to have a Hydrostatic Head (HH) rating of at least 10,000mm, taped seams to seal in-behind stich holes and either a DWR (durable water repellent) coating on the fabric or a waterproof membrane.

For example, Dryvent from The North Face & Omni-Tech from Columbia are DWR coatings, while GORE-TEX (used in many high-end branded jackets) and Pertex shield from Rab are membranes that allow sweat to escape and breath while keeping water out.

The value of taped seams is that without them - even the highest-rated HH fabric can still leak at pressure points like along stitched seams.

Yes - water resistant fabrics can handle lighter spots of rain or showers for a short period of time. Waterproof jackets and pants are made to stop water pushing through the face fabric and seams for far longer, this makes them the ideal candidate for outdoor activities.

DWR wears off over time through washes and general use. It is the product that makes the water "bead off" your waterproof when you first purchase it.

If this stops working, the fabric "wets out" which means while you are still waterproof, the water is absorbing on the face fabric which both blocks breathability and can make you feel colder.

Wash the jacket in warm water (no fabric softeners and no regular washing powder) use Tech Wash or Performance wash and then tumble dry on a low setting to reactivate. After this - you can either spray or wash-in (depending on which version you bought) your DWR which is normally called Reproofer, or Repel.

Tip - it might seem strange to heat a delicate product like this up, but the heat in the dryer is critical. It reactivates the repellency by essentially curing the DWR treatment you applied. Don't have a dryer? An iron can do! Set it on the lowest setting and put a towel or cloth between the item and the iron.