How to Install a Drainage System

If you’re installing a new landscape, or re-doing an existing, be certain to install a drainage system if you live in an area where the soil doesn’t percolate. By doing so you can move all the water to a desired location that would otherwise pool and create problems such as crown and root-rot of plants. You’ll also eliminate major problems, such as water under the home which can create sub-structure rot, and also prevent mosquito breeding areas.

One way to look at a drainage system is to compare it to our own vascular system. Without the proper plumbing and flow – things just don’t work properly. The pipe usually comes in two different products. The flexible polyethylene pipe is available in perforated and non-perforated. The other product available is the ADS solid type drain pipe. The differences will be explained as follows:

Flexible perforated and non-perforated:

This flexible ridged pipe comes rolled up as a 100 foot long product making it easy to haul home. If you don’t have a truck it will fit in a large trunk or the back seat of a large car. It’s commonly available in 3 and 4 inch pipe with larger sizes available for projects where a high volume of run-off is expected. Note that perforated pipe (which needs to be enveloped in rock and wrapped with fabric) should only be used in limited applications – and is prone to root intrusion and subsequent clogging.

ADS Solid:

This is the choice for commercial applications – often required by landscape designers and landscape architects. Also available in perforated and non-perforated pipe, this drainage pipe is most commonly available in 20 foot runs, therefore a truck will be needed – however, delivery is always an option.

Fittings:

Both types of pipe have all types of fittings to connect lengths of pipe, collection boxes, downspout connectors, y connectors to tie into main lines which allow for smooth integration of water-flow, reducers or bells which will tie together pipes of different sizes, and finally tee connectors which are used for a wide variety of purposes.

Installation:

Trenches are dug throughout the landscape in the most efficient layout as possible. If a complete loop can be installed in a residential project, this is best, as water will flow one way or the other to the desired location. This loop will often be run at the edge of the patio to pick up rain run-off, then continue thru the lawn area, where inlets will be installed in the low spots. As the 4 inch main line runs down each side of the home, inlets are installed, using tee fittings to capture any standing water or run-off from the neighbors’ garden. Down-spouts should always be tapped into the system as well – otherwise the flooding of flowerbeds can doom plantings.

Proper slope:

We all know that water runs down-hill, so as long as there is a constant down-grade for water to flow there will be no problem. Often landscapes have minimal fall and this issue becomes more critical. The general rule of thumb is to have at least 3 inches of fall per 100 feet of run. Try to keep the trench slope constant – without low dip areas – which will prevent a sluggish water-flow.

In closing, if you if fact live in an area where the soil type requires a drainage system for proper landscape management and plant health, save yourself future problems and costly repairs – and choose your pipe wisely.