If your footings are installed on the side of a steep hill, they may be susceptible to erosion damage or washout caused by water runoff. Over time, the side of the hill may begin to collapse, and this action can cause the nearby footings to fail. You should use the 7-foot rule, which states that the bottom of the footing should be at least 7 feet laterally from daylight. Heavy rains on uneven ground can cause tremendous damage to structures. Sandy and silty soils are more likely to erode than clay. Soil erosion can be controlled by providing adequate vegetative ground cover to hold the soil in place.
Grass and shrubs can provide a living barrier that will absorb the impact of rain drops and slow the flow of water runoff. Try to divert water away from the footings by using gutters. You may also want to dig your footings deeper than normal and tie them together with a concrete trench using rebar. In severe cases, you may want to have conical footings professionally installed specifically to the conditions of the site. In these cases, you will definitely want to consult with your local building inspector. We recommend always overbuilding to prevent even the smallest chance of a tragic accident.