Septic tank by a lake How to Spot Areas Where one Should Not Expect to Find (nor Install) the Septic Drainfield

  • UNLIKELY DRAINFIELD LOCATIONS - CONTENTS: How to find the septic drainfield or leach field - where not to bother looking - the last places you expect to find the soakaway bed or soakpit. Video here shows where septic system components are probably not located. Where not to expect to find septic system components
  • POST a QUESTION or READ FAQs about how to rule certain site areas out of the search for a septic drainfield or tank
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When looking for the soakbed or leach field it helps to know where that component is not likely to be found:

How to find the soakaway bed, leaching bed, drainfield or drywell for a septic system or seepage pit - method 5: ruling out certain locations. If you can't find the septic tank or drainfield this article helps direct your search by describing visual inspection of the site that will show areas where you can pretty much rule out expecting to find a buried septic tank or drainfield.

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A Guide to Finding the Drainfield - Part 5: unlikely septic system component locations

What areas are least likely to contain the drain field, or if they contain a drainfield, are likely to be a problem?

This article series and our accompanying septic system location videos explains how to find the leach field or drainfield portion of a septic system. We include sketches and photos that help you learn what to look for, and we describe several methods useful for finding buried drainfield components. (

Septic drain fields are also called soil absorption systems or seepage beds.)

The septic system video#4 at right describes walking a homesite by a lake in order to reason that the drainfield, which must be not only uphill from the lake but in this case uphill from the septic tank too, cannot be located in the front yard, even though that looks attractive for a drainfield. In the center of the yard we spot the well casing - end of story.

The septic field should not be located here.

A septic pumping system will be needed and the drainfield will have to be located elsewhere on the site, and at a good distance from the well. More videos on septic system location & maintenance are at SEPTIC VIDEOS.

Site areas too close to a drinking water well cannot be used for septic drainfields. See Table of Required Septic Tank, Drainfield, & Well Clearances if you need to reference typical septic component clearance distance guidelines. Our video at the top of this page demonstrates how we discover where the well is located and why that should preclude finding the septic fields in an area that otherwise looked pretty attractive.

PHOTO of a failed drainfield leaking across rock on a steep site.

[Click to enlarge any image]

Uphill areas, areas that are higher than the elevation of the septic tank are not a first choice to contain the drainfield or leaching beds.

Unless a septic pump or effluent pump system are installed (you'd find wiring, and perhaps alarms) the drain field is going to be at or below the elevation of the septic tank. In other words, down hill from the septic tank since effluent has to enter a conventional drainfield by gravity..

Naturally nothing prevented the installer from burying the leach lines very deeply in an area which is, on the surface "uphill" from the tank, but this would be an extra costly installation (more excavation) and also it would violate good design (leach trenches too deep).

Rocky areas like this should not contain a septic drainfield but sometimes they do - even though a conventional septic system won't work on rock: such as the failed septic system shown at left, and areas where bedrock is exposed on the surface won't make a normal absorption field.

But beware, we've found non-functioning systems installed in just such a location as the rocky, steep site shown in the photo at left. The wet marks were water from the septic system leaking across the hillside.

Photo of a constructed wetlands septic area

At the upper center of the photo above you can see straw that the owner's contractor piled atop of the septic tank in anticipation that any problems would be hidden from view.

All we had to do was walk downhill at this steep rocky site to see these signs of a totally inadequate septic system installation

Septic effluent running over bare rock

Swamps or low wet areas, unless the site is using a constructed wetlands for effluent treatment (such as we show in this area of Mexico in our photo above) should not contain conventional drainfields.

Photo of a forest: Heavy trees means unlikely area for a septic field

If the septic fields are too close to a wet area like this the property may be disposing of septic effluent but a conventional tank and drainfield spilling untreated wastewater effluent into a swamp, stream, or lake, is not properly treating it and is contaminating the environment.

Areas with Trees: thickly forested areas are unlikely to contain a drainfield, first because of the tree root-drain-clog problem and second because the backhoe operator would have a heck of a time manipulating the excavation equipment in such a tight area.

If there is no room to operate a backhoe it is unlikely that there is a recently-installed drainfield in that area.

This area on a homesite in the Northern U.S. is an unlikely spot to place a drainfield - certainly the presence of trees close together means a backhoe has not been in here digging in many years.

But don't rule out a very old, overgrown, and ruined drainfield in such a spot at an older property.

Hiding a water well - no place for a septic field

Site areas too close to a drinking water well cannot be used for septic drainfields, as we demonstrate in our site-walking septic-locating video at the top of this page.

Our septic search photo at left shows that some well locations are pretty obvious - we don't expect to find the septic tank or drainfield within 75' to 100' of this spot - but we might, depending on the age and size of the building site.

Sites too close to a lake or stream should not contain the septic tank and certainly not the drainfield - but they might

Septic tank by a lake

Especially at older, unsupervised, or remote rural properties, the temptation to simply route effluent leaving the septic tank to a stream, lake, pond is sometimes overwhelming (though unsanitary and illegal).

This is particularly true at sites where the soils into which one would have to put the drainfield are rocky, wet, or where the drainfield has previously failed.

We discuss this problem installation further at SURPRISING DRAINFIELD LOCATIONS.

Septic Drainfield Location Articles


Continue reading at VISUAL CLUES LOCATE the DRAINFIELD or select a topic from closely-related articles below, or see our complete INDEX to RELATED ARTICLES below.

Or see SEPTIC TANK, HOW TO FIND for details about finding the septic tank or chamber or drywell or seepage pit.



Or see How to Find the Septic Tank. More videos on septic system location & maintenance are at SEPTIC VIDEOS

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UNLIKELY DRAINFIELD LOCATIONS at - online encyclopedia of building & environmental inspection, testing, diagnosis, repair, & problem prevention advice.


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Questions & answers or comments about how we can rule out certain areas as plausible locations for a septic tank, drainfield, drywell, cesspool, or soakaway bed by examining terrain features and location of a nearby well, stream or pond..

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