Hydrostatic pressure occurs when the soil surrounding a foundation becomes saturated with water from heavy rainfall, melting snow, or poor drainage. This water fills the voids between soil particles and exerts a powerful lateral (outward) force against the foundation walls.

According to the provided content, this pressure causes cracks and leaks through the following process:

• Exceeding Material Strength: The sustained lateral force eventually exceeds the tensile strength of the concrete or masonry. This leads to the formation of horizontal cracks (often near the base or midpoint of the wall) and stair-step cracks in block walls.
• Wall Deformation: Over time, the unrelenting pressure can cause foundation walls to flex, bow inward, or lean, which widens existing fissures.
• Water Intrusion: These cracks create a direct path for moisture. Because the water is under pressure, it is forced through the cracks or even through porous masonry, leading to active seepage, damp spots, and the formation of efflorescence (white powdery mineral deposits).
• Soil Expansion: In areas with expansive clay soils, the soil swells as it absorbs water, further compounding the lateral force and accelerating structural deterioration.