MebaruWaterproof ratings (hydrostatic head, measuring in mm) for tents are in the range of 1,500-5,000mm, so this is the most waterproof fabric tent generally available. MSR tents, for example, are all 1,200-1,800mm. Tents from Rab, Terra Nova, and TarpTent are all 3,000-5,000mm.
Rain jackets are different, due to the pressure put on the fabric, and therefore the the rating range is more like 10,000-30,000.