How To A Find Septic Tank With A Metal Detector - Our 2021 Guide!

How To A Find Septic Tank With A Metal Detector – Our 2021 Guide!

Our Guide To Finding a Septic Tank With a Metal Detector

If you live in a rural area you might find that your sewage line relies on a septic tank to treat your sewage, when this tank gets full or starts to have issues, you will need to be able to locate the tank to fix the problem. 

To find a septic tank with a metal detector you will need to find where your main sewer line is and locate from there, if the material of the tank is made out of concrete or steel you can use a metal detector for the search.

In our guide below, we will cover how septic tank systems work, when you need to use a metal detector to locate one, what else you need and how to find your septic tank with some easy to follow steps.

How Do Septic Systems Work?

Before we can get into how to locate your septic tank with a metal detector let’s discuss how these tanks and drain fields connect your house so that you can understand how to locate one properly. 

The septic tank itself operates as a waste storage system that is connected to the sewage drain pipes leading to the house, the concrete tanks are then buried underground where the waste inside is split into three layers; scum, effluent and sludge.

This is all then connected to the drain field, the concrete septic tank takes liquid sewage through layers of gravel and soil and then becomes the groundwater, the organic matter is then eventually broken down.

When To Use a Metal Detector To Find Your Septic Tank

There might be a time when the sludge in your septic tank builds up and gets too full, which cause the drain pipes to clog up and stop working properly, in this case, the septic tank then has to be pumped out to remove the sludge inside of it.

Locating the septic tank is not always easy however since you have to do a property search for it, (this is where the metal detector comes in handy), luckily most septic tanks are made out of concrete and have steel arms, so you need a sensitive metal detector for the job. 

What Do I Need To Find a Septic Tank

To find a septic tank you need to use a type of metal detector with great discrimination settings, preferably a sensitive detector since we will be trying to find steel buried in the ground which is not the most conductive of materials. 

You are also likely to find a lot of trash in the soil, having an advanced detector with discrimination settings for this can save you time searching through layers of soil.


We’ve listed some other important tools you need for the search below. 

  • Plumbing cleans out snake. 
  • Flushable transmitter. 
  • Shovel. 
  • Gloves.

How To Find Your Septic Tank With a Metal Detector 

Septic tank detection takes patience, one way to save you time is by understanding where it is on the maps of your property, you can then go in a search with the metal detector. 

We’ve listed all the important steps down below. 

Steps To Locating The Septic Tank 

  • Step one – First of all, figure out where your main sewage line meets your septic tank drain line, it will be a pipe on the outside of your house connecting into the ground. 
  • Step two – Now try and find the public records for the septic sewage tank points in your location and property, we know this might be a long shot, but it’s worth a try, you could also publicly request the records.
  • Step three – Depending on the history of your house will likely determine the material of your septic tank. For example, plastic septic tanks are rarer due to their lack of durability and have been around since the 1980s, fiberglass septic tanks are more common like steel thanks to them being stronger, concrete tanks are used often, but can crack in hot climates.
  • Step four – If the septic tank turns out to be concrete or steel you can now use your stronger metal detectors to locate it.

Common Places Where Septic Tanks Are Located 

If you can’t find the permit for your house and you struggling to locate an area your septic tank could be in we’ve listed a few common places you could try to look below.

  • Near a well. 
  • Trees. 
  • Lots of weed growth. 
  • Bald places. 
  • 5ft away from your house. 
  • Bumps. 
  • Under paved driveways.

Finding The Septic Tank With Your Metal Detector 

  • Step one – To find your septic tank with your metal detector use the permit plan to map out the location, look on the diagram and try to find the point where the drain line meets the house, from here you can install where the septic tank belongs. 
  • Step two – Turn your metal detector on set to high then sweep the device side to side while you are searching around the pinpointed area. 
  • Step three – Mark down the places on your diagram where your detector starts to get the highest signal strength. 
  • Step four – Once you have searched the drain field go to the place with the highest signal strength on your detector, this will likely be where the tank lid handles are. 
  • Step five – Now start to dig on this location anything between 10cm and 1.4m below the surface until you find the tank lid. 
  • Step six – Once you’ve found the location of your septic tank you can put a septic tank riser, this is a shaft that allows you to access the tank with ease rather than digging down.
  • Step seven – If you still haven’t been able to find your septic tank then it might be best to use a cleanout snake, simply insert the cleanout snake till it reaches the septic tank end and follows it down with your metal detector until it reaches the tank opening.

Frequently Asked Questions About Finding a Septic Tank With a Metal Detector

Can you find plastic septic tanks with a metal detector? 

Unfortunately, if you have a plastic septic tank or fibreglass tanks then you will not be able to use a metal detector to locate them, instead, you will need to use a soil probe, touch lightly when using the soil probe and make notes when you feel any resistance in the ground as these could be likely areas.

Do bigger coil sizes help to find a septic tank?

Bigger coil sizes can help you find your septic tank if it is located deeper in the ground but it having a larger size does make it more likely to pick up trash since it’s harder to discriminate.

What is a septic tank riser?

A septic tank riser is part of the septic tank that sticks out at the top, this makes it much easier to locate the tank rather than having to detect it.

Will a regular detector work to find a septic tank? 

A standard metal detector should work okay to find a septic tank, higher quality models however are better at detecting low conductive metals such as aluminium.

What is a plumbing cleanout snake?

A plumbing cleanout snake is a pipe that is inserted into pipes to clear out blockages, or in our case as a conductive source for the metal detector to pick up a signal from.

Why can you find septic tank lids with a metal detector?

Most septic tank lids are made with metal bars for the handles which is why they are detectable more so than the tank material itself.

What is the most popular septic tank material?

Most septic tank material is either concrete or steel due to them being durable, you can find tanks made out of plastic tanks or fibreglass too but these tend to be on newer houses and are less durable.

How do you know if you have a spot of signal?

If you have a spot of signal on your detector then you will likely hear a change in the detector alarm, the faster and stronger the beeps the more likely you are to find a target or the septic tank in this case.

Last Words 

To conclude, you can indeed find a septic tank with a metal detector as long as it’s made out of steel or concrete since these are conductive materials. The best way to locate a septic tank is by knowing the age of your house as this will indicate the type of tank and the location, you can always try using a plumbing cleanout snake in combination with a detector too.

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