Septic drainfield on a steep slope Septic Drainfield Installations on Steep Slopes

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Steep slope septic drainfield systems.

This article describes the installation of septic drainfields or leach lines on difficult terrain such as on steep slopes where a property disposes of wastewater using a septic tank and drainfield.

We also provide a MASTER INDEX to this topic, or you can try the page top or bottom SEARCH BOX as a quick way to find information you need.

Guide to Septic Installations on Steep Slopes or Stepped Slopes

Steep terraced slope septic © D Friedman at

Also see Sewer or Septic Line Installation at Steep Sites, and for people conducting a septic system inspection or test, also see DIFFICULT SEPTIC SITES. Technical reviewers are welcome and are listed at "References." Citation of this article by reference to this website and brief quotation for the sole purpose of review are permitted. Use of this information at other websites, in books or pamphlets for sale is reserved to the author.

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Our photo above illustrates terracing used by the excavator during a septic drainfield installation. In addition to the text of this article (below), readers concerned with septic installation advice for steeply sloped or rolling sites should see these articles:

Guide to Installing Steep Slope Septic Drainfield Systems

Photograph of installing plastic sewer drain line piping

Installing Septic Drainfield Piping on Steep Slopes Located Downhill from the Septic Tank - Uniformly Sloped Land

The sketch at page top shows an installation approach for septic drainfields across a steep or rolling slope. The photo just above illustrates sewer line piping down a steep slope to a septic tank and seepage pit system located in a flat area below the hillside. But what do we do if the septic effluent absorption system or soakbed itself has to be installed along a steep hillside? Here are some specifications.

Installing Septic Drainfield Piping on Steep Slopes Located Downhill from the Septic Tank - Rolling Land

Gravelless septic may curve on hilly sites

Drip line septic system sketch

Why Drainfield Effluent lines need to be properly sloped

Septic drainfields that treat and dispose of clarified wastewater effluent using gravity need to be properly pitched and never sloped too steeply. Otherwise effluent will run too quickly to the low end of the drainfield line and gravel trench where it is likely to simply break out to the property surface.

If you have to install a conventional perforated pipe and gravel trench drainfield on a steep slope you'll need to run the trenches along the slope or parallel to the fall line, stepping down the slope from trench to trench.


Continue reading at SEWER or SEPTIC LINE INSTALLATION at STEEP SITE or select a topic from closely-related articles below, or see our complete INDEX to RELATED ARTICLES below.


Or see MEDIA FILTER SEPTIC SYSTEMS - a series of articles on types of media filters such as sand beds, foam cubes, peat septic designs



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STEEP SLOPE SEPTIC DESIGNS at - online encyclopedia of building & environmental inspection, testing, diagnosis, repair, & problem prevention advice.


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