Proper Grading of House Landscaping

Considerations

• Ideally the house is the high point on the property. Unfortunately, that isn't always the case. Look at the property from several angles to determine the best way to direct water away from the house and into an approved site. As you plan landscape grading, take into consideration any features on the grounds that you should not disturb. Trees are a prime example. Stake a line or erect a construction fence to keep heavy equipment well beyond the drip line of an established tree's canopy. This prevents soil compaction, which can eventually kill the tree.

Local Codes

• You may not be able to simply drain the water away from the property and allow it flow into a storm drain or onto your neighbor's property. Many city ordinances prohibit this. Instead plan on grading the property to an area within 5 to 10 feet of your boundary and then dispersing the excess water in some manner.

Slopes

• Some areas of the lawn see more foot traffic than others. Direct as much water as possible away from those areas. If you have a patio or a flat play area planned, create a slope of no more than 2 percent. That allows a fall of less than 1 foot for every 50 feet of distance. Driveways should optimally have no more than a 5 percent slope along the crown with a 2 percent slope on each side to allow drainage. Walkways should ideally have no more than a 3 percent slope with 2 percent allowed for side-to-side drainage. As you plan the lawn drainage for the rest of the property, keep in mind that you must mow grassy areas or plant vegetation of some sort to prevent erosion.

Swales and Drains

• Because the goal of lawn drainage is to get water away from the house, you must plan for swales and drains to carry it away. A swale is a small, shallow drainage ditch created to direct water to a designated area. It can be so narrow that it can run alongside a sidewalk or driveway or be part of a flowerbed or landscape feature. It might be wider, depending on how much water it needs to carry. No matter how large the swale is, take steps to cover it with vegetation or use erosion control measures, such as fabrics and large rocks, to keep the swale from eroding.

  Drains may be perforated pipes buried in low-lying areas that collect the runoff water and direct it to an area for dispersal. Gutters may run directly into drainpipes. Typically, the drainpipes are set at a 2 percent slope. It's possible to direct the drains to a collection container so you can use the runoff water for watering the lawn or garden.