Good drainage is essential in a garden. Not only for practical reasons — no one wants permanent puddles outside the back door — but also for the benefit of plants, as they may suffer in poorly drained areas.

Poor drainage may be caused by soil compaction; a common problem around new homes. Impermeable clay subsoil or a naturally high water table may be another reason. Discover what type of soil you have, and also make a note of low spots and wet areas.


Grading is the movement of soil. When dealing with garden design, grading provides drainage for surface water, areas for play, and paths for movement within the garden. Always consider the effects on drainage when grading for any purpose. After drainage, terracing to increase the amount of flat land is the most common reason to undertake grading activities.

While it is important for the homeowner to plan and visualize the results of potential grading changes, it is best to consult with professionals for significant grading projects. Contact your local planning department to learn about the possible need for permits.

Level or Sloped

Few properties are perfectly level. The slope (steepness) may be only a few inches from end to end or so severe that it’s difficult to walk up and down the property. To make the most of your property, ask yourself the following questions:

  • Does your property have a slope? The existing slope will determine what actions should be taken. Ground covers may be the answer for long, gentle slopes. Most ground covers (not grass) will probably stabilize a 1:2 (1 foot of rise per 2 feet of run) to 1:3 slop e. Lawn, or bark mulch, should not be placed on a slope with a ratio greater than 1:2 feet of run.

This slope should not have been planted with lawn. Too steep to allow irrigation water enough time to penetrate the soil, leaving thirsty, brown areas.
sloping garden
  • Do you need to create easier access to an elevated area? Steps, stairs, and ramps allow for change in elevation. Avoid the use of a one-riser step. Often too shallow to be noticed, they cause tripping.

  • Would you like or need terracing? Railroad ties or blocks may solve the problem.

Many areas of Santa Clara County have clayey soils that are slow to drain, so planning for adequate drainage in your landscape is important.
Good drainage