No one thinks about drainage until it rains very hard leaving little lakes around the back of the house or down the side yards. In fact, Southern California doesn’t get much rain during the summer but when it does rain, it comes down just as hard in the Winter for a short time as it does in much of the country.
California is a desert state and many of the soils are ocean bottom or a base high sandy clay. This means that the absorption rate of water can be good in some areas and not so good in others.
In many newly developed tracts around San Diego, most lots are sloped towards the street to prevent run-off from going into the neighbors-property down below or from side to side. Usually the water makes its way to the street and the waiting storm drains located there.
From the street, the heavy run-off can then travel by large storm pipe to a lower running river or be piped straight to the ocean where the run-off mingles with the saltwater and goes back to the sea.
This system works well in most areas but sometimes a low-lying backyard or poor drainage can interrupt the cycle.
Most good Landscape Contractors tilt the new concrete patio away from the house into surface drains in the planter areas or dedicated soils. Creating a cupped area with a drain in the middle of the concrete often creates a wet pooling area or collection basin that can back up from any roots infiltrating the drainage pipe 30-40 ft. away.
Using a snake or a wire fed drain clearing device can work in the initial stages of new construction but the thin wall of the drain pipe, usually a plastic material will break when faced with a high-speed drain snake or a wire feed traveling at high speed into a 90-degree turn.
Glued joints and solid pipe are the best for keeping roots out and clearing the pipe is best accomplished using a garden hose with full pressure water. This helps lubricate the hose, liquifies the mud or soils and removes many of the blockages that occur over time in the drain pipe below grade.
Sometimes, the soils are so clay like that the concrete color will mottle if the concrete is cupped to capture run-off in the concrete. This happens because the water in the concrete and soils becomes trapped and will not run off under the concrete to the planter areas as recommended.
The best way to install drains in a landscape is to think 15-20 years down the road. By installing the pipe in the soils, this can be removed or cut and cleaned out without much difficulty because it is not underneath the existing patio space up above.
Drains should always be installed with the thought that they need to be replaced in the future and concrete is better cut, because of cost, than removed in order to install a new channel drain or a new pipe drain in the planter areas that have been dedicated just for that purpose.
New drainage is always easier to replace with a little bit of digging than it is to remove c