LARGER IMAGE: having a general idea of what septic components are helps you find where they may be locatedA Guide to Possible Septic Tank Locations

  • POSSIBLE SEPTIC TANK LOCATIONS - CONTENTS: A Guide to Possible Septic Tank Locations helps us determine how to find the septic tank and drainfield . Where to look for the septic tanks, septic tank covers, or septic tank cleanout lids. How to find the septic tank - where to look
  • POST a QUESTION or READ FAQs about how to find the septic tank when we have no idea where to start looking

Septic tank location guide based on site characteristics:

This document provides procedures for finding a septic tank by considering what septic tank locations are even possible at a particular site.

This article tells us how to locate a septic tank when it's placement is not already known or when the location of the septic tank is not visually obvious.

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How to Find the Septic Tank by Looking Outside the Building

LARGER IMAGE: melted snow may mark septic tank locationThe photo at page top shows a terrible way to find the septic tank - by driving over it and getting stuck. A survey of a building site for locations that could reasonably be expected to house a septic tank or drainfield is a useful step in understanding where septic components could be buried.

POSSIBLE TANK LOCATIONS - Site Conditions Determine Possible Septic Tank Locations

If you have no idea what a septic system is, see the "More Reading" articles below. If you have a general picture of what the typical septic system components are, how big they are, and how they are connected together, you can have a reasonable idea about where these items might even fit at a property.

[Click to enlarge any image]

In the example shown at left, our client is pointing to an area of obvious fill across the yard in front of his new home.

Everywhere else at this home site was thick with trees and also was swampy. The septic system tank and fields were almost certainly going to be in this (improperly prepared) mounded area.

Look in the distant photo at the original grade and you'll see that the contractor put the mound in a natural swale which turned out to be a natural creek - the system lacked sufficient fill soil - effluent moved from the leach field to the stream the contractor had buried, and simply appeared at the end of the mound. But that's another story.

Look around the building site with these septic tank location tips in mind

  • The septic tank is probably on the property - though in unusual cases such as the subdivision of a family property it might be on the neighbor's land.
  • Septic tanks need space to be buried-in, normally eight feet or more of soil, though special "low boy" tanks can be placed in as little as four feet of soil and advanced wastewater treatment systems can be above ground entirely. (You won't have trouble seeing advanced aboveground systems.
    See SEPTIC TANK DEPTH for a discussion of soil depth to the top of an installed septic tank

Septic tank access riser at a Norwegian property (C) Daniel Friedman inspected in 2008

  • Often septic tanks are located close to buildings (perhaps 10 feet away) in areas where there appears to be space for the tank and adequate soil depth, but at a problem site such as a house built on a rock cliff or on a steep slope, the tank may have been located at some distance. Look for other property areas which are not thickly populated with mature trees. (It would be foolish to plant trees over the septic components but people may do so.

    But at a fairly modern site, the excavator digging to place the septic tank won't have jammed her backhoe among huge old close-together trees.

    Shown at above-left: an easy-to-access septic tank riser at a property we inspected in Norway.
  • Look for the septic tank (and drain fields) downhill from the building: unless a pumping system is installed (you should find switches, alarms, wires), the septic system is working by gravity. The tank will not normally be far uphill from the building.
  • Look for the septic tank uphill from the building: if a pumping system is installed the tank may be anywhere, but still we needed space and soil depth to locate it. If there is an obviously "constructed" area of earth fill (a mound system) serving as a probable leach field, the tank may be at the near (to building) end of that mound.
  • Drainfield Layout: gives septic drainfield or leaching bed shape, size, and placement considerations


Continue reading at SEPTIC TANK DEPTH or select a topic from the More Reading links shown below.

Or see SEPTIC VIDEOS showing how to find the septic system, septic tank, & septic drainfield

Or see SEPTIC DRAINFIELD LOCATION - how to find the leach fields.

Suggested citation for this web page

POSSIBLE SEPTIC TANK LOCATIONS at - online encyclopedia of building & environmental inspection, testing, diagnosis, repair, & problem prevention advice.

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