Since hydrostatic pressure is simply the weight of water around your home, rainfall absolutely increases this level of pressure. However, the increase is usually minor.
Rain Raises the Water Table
Even a small amount of rain will add to the level of hydrostatic pressure in your Grand Junction, Colorado, home, but unless the rainfall is significant and prolonged, it is unlikely to add enough water weight to cause serious damage to your home. This is not the only thing you need to worry about when rain starts falling, however, as any amount of rainfall will affect the water table.
The water table is the level at which the soil or substrate is permanently saturated with groundwater. Rainfall can cause this level to rise closer to the surface. If the water table reaches your foundation or basement walls, the amount of hydrostatic pressure they experience will rise heavily and quickly. This can cause damage very easily.
Flooding Adds Serious Pressure
Localized flooding because of heavy and persistent rain, drain overflow, or a rise in the level of a local river presents real damage to your property. Primarily, serious flooding can lead to water entering your home and causing widespread damage to its structure and your belongings (as well as posing a risk to your health and well-being). However, even less severe flooding can increase hydrostatic pressure dramatically.
After all, hydrostatic pressure is about the water in the soil, not water in your home. So even if the flooding in your local area remains low, you should check your home for signs of damage, as the water table will be much higher than usual. Look for cracks, unevenness in your walls, and dips or bulges in your flooring.