Confused about tent water ratings? Are you confused about terminology such as “hydrostatic head, water rating, water column and PU coating”? A tent’s waterproof properties are measured using a rating called its hydrostatic head. Put simply, this equates to the amount of water in millimetres that the tent’s fabric can tolerate before any water droplets seep through. So, if a tent has a hydrostatic head of 3000mm, it can hold a 3 metre column of water on its surface before any leaks through. For groundsheet ratings, pressure needs to be taken into consideration. When you walk over the tent floor, pressure is applied to a small area that can force water through the groundsheet fabric if it has a low rating. Coleman® uses polyethylene (PE) groundsheets which are relatively heavy but provide guaranteed water protection. PE groundsheets are ideal for family and active tents where a very light weight and small pack size are not essential. 3000 mm 2500 mm Height of column of water 2000 mm 1500 mm 1000 mm 0 mm The Ministry of Defence classifies a hydrostatic head of 800mm as waterproof Coleman Tent Models Da Gama Galileo Instant Tents Darwin Plus Tasman 8