LARGER IMAGE: unsafe septic tank cover discovered by simple exploration - we roped this area off and placed heavy plywood over the opening - it was by a children's play area.A Guide To Septic Tank Covers

  • SEPTIC TANK COVERS - CONTENTS: a guide to septic tank covers, finding, types, and septic tank cover safety. Assuring the septic tank cover is safe. Where to look for the septic tanks, septic tank covers, or septic tank cleanout lids
  • POST a QUESTION or READ FAQs about septic tank covers, septic tank cover strength, collapse, or safety concerns
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Septic tank covers, openings & access ports:

What are the types of septic tank covers, how do we assure the septic tank (cesspool, drywell, or seepage pit) cover is safe;

How deep is a septic tank cover buried, & do we find & remove septic tank covers?

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SEPTIC TANK COVERS - Once the Septic Tank has Been Located How Deep is The Septic Tank Cover & Is the Cover Safe?

Concrete septic tank cover photo s howing the cleanoutSeptic Tank Cover Depth & location

Tank Cover Depth: How deep will the septic tank cover be?

The top of the septic tank is often about one foot below the surface. But this depth varies alot.

However the septic cover can be several feet deeper.

If you note the depth at which the waste line leaves the building foundation wall, say perhaps 3 ft. below the top of soil (grade level) then if the site were dead flat and if the tank were

Found 12 feet from the foundation wall, at a typical waste line slope of 1/8" to 1/4" per linear foot of run, the septic tank's entry port for the waste line would have to be roughly 3 ft. 3" below grade level.

Obviously if the site is not flat these septic tank cover depth estimate numbers change.

Septic Tank Cover Safety Procedures

Be absolutely certain that the covers and cleanout access covers over the septic tank are secure and durable so that it will be impossible for someone to fall into the tank (which is often fatal), and so that a child could not remove the cover.

If your septic tank is in an area where vehicles may drive over it, special heavy-duty rated covers are available. Discuss this option with your septic tank contractor.

LARGER IMAGE: unsafe septic tank cover discovered by simple exploration - we roped this area off and placed heavy plywood over the opening - it was by a children's play area. PHOTO of the septic tank cleanout cover.

If there is the slightest doubt about the condition of the septic tank cover (such as seeing subsidence over the tank location) you should rope off the area and prevent anyone from walking over it, again because falling into a septic tank is likely to be fatal.

Reader Question: septic tank cover collapse

11/28/2014 Scott C. said:

I have a septic system with a power assited pump tank. The lid collapsed under the weight of the soil it was buried under. There was about 3'2" of clay type soil that the installer covered it with. The lid thickness is 4". Is that up to standard for that much soil? - [This question was originally posted at SEPTIC TANK DEPTH]



If you want to investigate the adequacy of the lid over a septic tank you need a bit of data. Septic tanks are indeed rated for different weights and loads.

The thickness of the septic tank lid alone is not enough to know whether or not it was adequate - as we don't know if it contained steel reinforcement or if it did, on what spacing and using what material, nor do we know the quality of the concrete, nor its history (e.g. prior vehicle traffic over the tank) nor do we know the septic tank and size.

Reader Question about septic tank cover security regulations in Alberta

04/30/2015 Septic Tank Lids said:

Can you please inform me of the Regulations in Alberta regarding Septic Tank Lids?

We have a concrete Bell & Siphon and I notice the lower and smaller lids (one form each compartment) being are left at the top on the larger lids and under a cover on our concrete patio.

When I question the owner of the pump truck company...he said "that is a good place for them as they are a nuisance...they have to pull them up with a hook.... they get stuck with dirt...and the metal hooks break...and then they have to get down and smash them with a mallet". We have had the same tank system for 40 years and keep it covered and never had a problem until I noticed this recently, that someone had thrown the lower lids on top of the larger lids and under our cover. THak you Jane
This question was originally posted at GRAVITY/SIPHON DOSING SYSTEMS.


Sure STL:

Here is an Excerpt from the Alberta septic tank code Access Opening Lid/ Cover

1) All access openings shall be equipped with a secure lid or cover.1

1 Intent: Sentence (1) — To increase safety by preventing unauthorized or accidental entry into the access opening of a septic tank or holding tank. Acceptable protective measures include, but are not limited to, a padlock, a cover that can only be removed with tools, or a cover having a minimum weight of 29.5 kg (65 lb).

2) The opening of a manhole access that extends above ground shall be insulated to an equivalent R-8 insulation value to protect the tank contents from freezing.

The handbook offers this additional commentary on these practices:

It is imperative that the lid or cover of the manhole access opening be secure to prevent anyone from accidentally falling into a tank. Once fallen into a tank it is essentially impossible to get out without help. This securing of the access lid must be provided at time of installation and is an ongoing responsibility of the owner to ensure it remains secure.

During periods of time the occupants are away on a holiday for a number of days or in time of very low flow the tank is much more susceptible to freezing without this insulated lid.

In sum, if the cover over your septic tank could be moved by a child so that someone could fall in, the risk is a quick and ugly death. Be sure the covers are safe.


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