How to Find a Septic Tank and Manhole Cover


Find Septic Tank Lid Cover

Often people e-mail me to ask me where they can find the septic tank cover for a septic tank, the manhole or how to find a septic tank itself. To which the answer is always: "I don't know". In this Plumbing How To we will show you that a septic tank and septic covers are never located in the same place, making the septic tank lid hard to find, even for the experts.

Check your building plans they often show you how to locate a septic tank.

Locating a septic tank, distribution box or septic covers can be tricky. The first thing to do is check your original building plans. these building plans will often show you the exact location of the septic tank or manhole covers for septic tanks, if you do not have your building plans, contact the local office of zoning to see if they have your plan on record. If the septic system is still new you have a good chance they will, but many states don't keep any of the older records. If they have a drawing of your septic system on file, it probably will not match the septic tank that is in the ground exactly, but it should be close enough. Also if you are able to find out which septic tank service installed the septic system they should be able to tell you exactly where the septic tank or septic tank lid is.

How to find out where a sewer main exits the house.

If none of that works you will need to identify where your sewer main leaves your house. If you've got a basement or a crawl space you need to check inside to look for a 4 inch black pipe, to see where it goes out of the foundation. If you do not have a basement or a crawl space, or your sewer main is underneath your homes foundation, you will need to go and look for the location of the lowest drain in your home. This is usually a floor drain and most likely also the area where the sewer pipe will leave your house.

Use a tile probe to find the pipes leading to the septic tank.

After you have found your sewer main and have an idea of where the sewer pipe leaves the house you will need to go outside to that part of the house and take a tile probe or a ¼” or ½” steel rod and start probing the area of ground right next to the foundation until you find the sewer pipe. But be careful, if you poke too hard you could end up poking a hole in the drainpipe, particularly if it is older type cast iron pipe.

Once you have found the main pipe you will want to move further to find the septic tank. Move a few feet at a time while probing the ground, tracking the pipe until you find the septic system. Most septic tank systems will usually be ten to twenty feet away from your home. After you find the tank you will want to probe around the septic tank it to get the exact outline of the septic system. Septic tanks and septic tank lids come in different shapes, you can have a round septic tank shape, a square shaped septic tank or a rectangular septic tank, but once you find its exact sizes and shape you can start digging. You will find the septic tank manhole cover can be in the very center of the septic tank, the lid for a septic tank can also be on the side of the septic tank intlet, or the lid of a septic tank can be on the side of the septic tank outlet, there can even be 2 or 3 septic covers, and there there can be none.

How to locate a distribution box.

Locating the distribution box should at least be a little easier. It is usually about ten to twenty feet away from the septic tank and sometimes you can see it just by looking at how your grass grows. Often the grass will be greener over the drain lines and if you can see the pattern on the lawn where the lines come together, there is your distribution box. Otherwise you will need to locate the distribution box in the same way we found the septic tank.

Remember that, locating a septic tank, septic tank lid or a distribution box is seldom a quick job, it usually is quite hard.

Some of the things you can find while locating your septic tank are:

  • Tight clay soils. Clay can be difficult not only to stick a probe into, but once its in, it can be very hard to pull it back out.
  • Rocky soils. You think you hit the tank so you start digging only to find a rock. And that can happen over and over.
  • Deep systems. More than 2 or 3 feet deep can be a real treat to track and dig.
  • With older systems you will find pipes that seem to twist and turn then disappear into nothing.

Therefore this kind of job should be left to Septic Tank Service professionals (some pumpers will only pump tanks, but they won't locate the tank). Often a good plumbing contractor will know just where everything is only by looking at your property. And if they can’t find it straight away, then they still have all the equipment and  plumbing tools to find the septic tank's lid faster then you probably will.

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