Water Repellency, Hydrostatic Head, and Breathability — What’s the Difference?
These terms are often confused, but they describe different fabric properties.
Water repellency refers to the fabric surface. A DWR or other repellent finish helps water bead up and roll off, similar to a lotus leaf. Some textiles also combine water, oil, and stain repellency.
Hydrostatic head measures how much water pressure a fabric can resist before leakage occurs. This is usually achieved through a PU coating, TPU membrane, or laminated construction. Outdoor shell fabrics commonly target around 10,000–25,000 mmH₂O, depending on the end use.
Breathability in waterproof fabrics usually means moisture vapor transmission, not simple air permeability. A common MVTR target may be around 10,000–15,000 g/m²/24h, depending on the membrane and test method.
Simply put:
Water repellency = water beads off the surface
Hydrostatic head = resistance to water pressure
MVTR = moisture vapor can escape
A good outdoor fabric needs the right balance of all three.
Water Repellency, Hydrostatic Head, and Breathability — What’s the Difference?
These terms are often confused, but they describe different fabric properties.
Water repellency refers to the fabric surface. A DWR or other repellent finish helps water bead up and roll off, similar to a lotus leaf. Some textiles also combine water, oil, and stain repellency.
Hydrostatic head measures how much water pressure a fabric can resist before leakage occurs. This is usually achieved through a PU coating, TPU membrane, or laminated construction. Outdoor shell fabrics commonly target around 10,000–25,000 mmH₂O, depending on the end use.
Breathability in waterproof fabrics usually means moisture vapor transmission, not simple air permeability. A common MVTR target may be around 10,000–15,000 g/m²/24h, depending on the membrane and test method.
Simply put:
Water repellency = water beads off the surface
Hydrostatic head = resistance to water pressure
MVTR = moisture vapor can escape
A good outdoor fabric needs the right balance of all three.
