# drive over septic tank?



## AllanJ

Assume it is a very bad thing. It is very possible for the tank to cave in.

You may be able to put timbers on the ground so most of the weight of the tree service truck is transmitted to the soil on each side of the septic tank. This requires great care since if the timbers shift and let the truck tires down on the tank, you're in trouble.

Driving over the leaching field is also very bad. Timbers will not permit this.

I would shop around for tree experts who can cut the tree down little by little by rappelling down it using ropes.


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## Mike Swearingen

Do NOT drive over a septic tank with anything heavier than a riding mower.
They will cave in. Period.
Mike


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## NateHanson

Mike Swearingen said:


> Do NOT drive over a septic tank with anything heavier than a riding mower.
> They will cave in. Period.
> Mike


Well, I wouldn't agree with that level of certainty, but true, you should not let a tree-service drive over your septic tank (and definitely not on your leach-field). 

Our septic tank is under a corner of our driveway. It's buried by about 2 feet of gravel. It has had cars parked on it daily for 15 years, and has not caved in.


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## almostdone

I had the same problem. I had to mark out the perimeter of my tank and leach field and instruct the tree guy to strategically manipulate their equipment so they would not get to close and cause major damage to my system. They were more than willing as they could also damage their equipment. I had access to locating equipment to help as I did not live here when it was installed and it is obviously very important to be accurate.


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## wooddocinc

*Sounds to me like the septic tank isn't the real problem*

Driving over the tank, or the leach field is just a symptom of the real problem....removing the tree. A reputable tree service should work with you on removing the tree with workers skilled in taking down the tree from the top down in manageble size pieces that can be carried by the crew out to the shredder. Contact a couple of tree services and get several estimates.


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## Tommy Plumb

99,999 of 100,000 times you do it nothing is going to happen. It's defiantly not a chance I would take though. Aside from property damage people can die. I remember when two years ago a landscaper drowned after a cesspool collapsed and he was trapped under his mower.


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## AtlanticWBConst.

Marlin said:


> ... I remember when two years ago a landscaper drowned after a cesspool collapsed and he was trapped under his mower.


 
UGH!!....


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## Mike Swearingen

All of the septic tanks that I've seen around here are low quality concrete poured into molds with no rebar and no plan to support anything with the lids but their own weight and a few inches of ground cover to hide them.
Most all that I've seen will not support any vehicle.
Things are made differently here and there. 
Mike


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## DefEddie

I have a similar question if I could butt in.
My septic is thankfully on the side of my house and nicely out of the way,but the lateral lines(leaching lines?) extend along the right side of my property extending to the road.
This is an acre,the house is facing south with most of the acre in the front yard. Septic stage right,driveway extreme left.
I would like to alter my driveway to make a circular driveway across the acre+ (I actually have 2acres,driveway I think is actually on the adjacent acre with the pond,more on that soon)
If I do this it will take the driveway pretty much in a half circle across the top of the lateral lines.
Is there any way I could build on top of these? Someone mentioned a foot of gravel and sand I think over the tank.
Could I add a foot of material and then build the driveway over the lateral lines?
Just something I would like to do,have to keep the old driveway as a service road to my shop and garage anyway but would like a circle drive for guest's.


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## Mike Swearingen

It depends on the soil type, I would think. If you have good, well drained sandy land, you "might" get away with driving across your drainfield lines with minimal damage. However, there will be compaction where you drive over them, which will limit their function there. Definitely do not pave or build over any part of your drainfield. That's just asking for trouble.
You can always move (replace) your drainfield to an area where you won't be driving or building anything over it. Maybe even a single line addition could handle the sectional loss of use by compaction.
With all of the above said, I've known people who drove over part of their drainfield area for decades (sandy land) with no problems, so who knows.
Mike


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## DefEddie

I'm in clay/rocky soil on the bottom slop of a small hill/ridge.
If compaction is what i'm worried about then clay isn't the best to do this with then is it?
I've never actually walked off the septic lines,I have the map drawn when the house was built a couple years ago though.
Guess it is time to walk it off and see how much I might need to drive over. Not sure if it is worth adding to the existing system simply to have the driveway though.
Got any links where I can learn more? Thanks for your help.


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## Mike Swearingen

Contact your local Health Department, the usual permitting agency, for more information and guidance on recommended septic system activity in your area. With that type of soil, your drainfield is probably fairly large.
Here, in good sandy soil, they only require a minimum of 210' of drainfield line for a three-four bedroom home (such as 3 X 70' lines from the dbox).
Mike


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## wire_twister

Here in the Ga clay, north central Georgia, we are required to install 100 feet of leech line for each bedroom.We can install the Infiltrator system and only need 50 feet for each bedrom.


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## DefEddie

I've got the on-site inspection report from the new install in front of me and the sketch of the layout is telling me:
Septic is 8ft east from house and there is a pipe on the other side extending 5ft to a square that says L(Ellis?)
It then goes North from L for 65 ft total.
The lateral lines go west,the first being 25ft north of the square with the L. There are 4 more lateral lines branching off every 10 ft after for the remainder of the 65ft total length for a total of 5 lateral lines. If I am deciphering this sketch correctly the lines lay out like this.
1st line is 5' 4" underground and extends West 50ft.
2nd line is 6' 2" underground and extends West 70ft
3rd line is 6' 8" underground and extends West 70ft
4th line is 7' 11" underground and extends West 130ft
5th line is 8' 5" underground and extends West 80 ft.

Am I reading the correctly? If they are that far underground why am I worried that much about compaction? I thought Lateral lines were only 6"-12" underground.
On the sketch the lateral lines are denoted as a dashed line with the length at the end and the other measurements are simply written above each dashed line,which the index tells me is an absorption line.

This tell you guys anything?
Sorry to threadjack,should I start a different thread? I want to know a little more about this stuff.


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## stallinc

Hey Eddie,

I don't see it is thread-jacking - very relevant to subject. The argumants against driving over the system was enough for me.

good luck with the circular driveway,
Chris


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## DefEddie

Don't really plan on building the circle drive anymore,as the wife has decided against it now.
But I would like to know more about the septic system and the lateral lines.


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## doggofast

I believe the numbers you are referring to....5'8"...6'2"....6'8"....etc...may be elevation measurements from a laser level or transit. They are not likely depth measurements for individual leach lines. Typically, leach lines would not be installed that deep. An inspector may record these types of measurements on a site drawing, or perhaps the septic installer put them on the as-built drawing.


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## DefEddie

That makes perfect sense as my front yard is a slope downwards.
I didn't see anything about depth of the lines though,how deep are they often put?
I'm not sure what code is yet,our code guy is way overworked and hard to get ahold of.


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## krogers58

*Never ever...*

You might get lucky, and park on the corner of your septic tank, and whatnot, but just imagine if you go through. The tank is ruined, and will need to be removed (think bio-hazard disposal fees) and the whole area will be treated as a bio-hazard. I don't think you can imagine how much it would cost to replace the tank, including any damage to the vehicle that goes through. There are special septic tanks which can be driven on, but they cost more and need to be installed a specific way. As far as leach fields go, same deal, you could go through, especially with the newer fields which don't always use 4" pipe, but use the larger pipes or vaults. Driving on a leach field also compacts it, which will shorten the life of your field. But, if you have an extra 10 - 40 grand laying around to gamble with, go for it. I've seen trees taken down by a tree service where they used a crane, and put the tree in a sling, and cut the base and lifted it right off the stump, and the put it right where they wanted to. There are many ways to skin that cat, but driving on the field or tank are a big mistake. You might get lucky or your luck might run out.


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## Arky217

On a similar thought, what about driving cars/pickups over the line going from the house to the septic tank ? For schedule 40 pvc, how far would the line have to be buried to be safe ? How about for schedule 80 pvc ?

Arky


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## Daniel Holzman

Septic tank construction varies by jurisdiction. Where I live in MA, the minimum rating for a septic tank is H20, meaning that it is designed for 16,000 lb loading over two tires. A heavy tree truck could well exceed this loading, and of course your septic tank might not be designed to H20, could be much lower rated, or maybe not rated at all. Almost certainly a bad idea to drive over the tank with a heavy truck. If you know for sure that you have an H20 rated tank, you can certainly drive a pickup over it, I have done it on several occasions over my tank, no problem.


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## Arky217

Daniel Holzman said:


> Septic tank construction varies by jurisdiction. Where I live in MA, the minimum rating for a septic tank is H20, meaning that it is designed for 16,000 lb loading over two tires. A heavy tree truck could well exceed this loading, and of course your septic tank might not be designed to H20, could be much lower rated, or maybe not rated at all. Almost certainly a bad idea to drive over the tank with a heavy truck. If you know for sure that you have an H20 rated tank, you can certainly drive a pickup over it, I have done it on several occasions over my tank, no problem.


Thanks Daniel, but I didn't mean driving over the septic tank.

But the main drain line going from my house to the septic tank will traverse across
the only space that I have to drive to the back of my house (long story, the house is on a narrow ridge).

I am planning to use schedule 80 pvc for that line and was wondering how deep 
I would need to bury it.
If that's not a good idea, maybe I should transition to cast iron pipe for the area where I need to drive over ?

Arky


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## Polly003

Been following this and would be interested in the reply to Arky about how far deep pvc needs to be buried under an area that might someday be driven across. Schedule 40? Schedule 80? Not necessarily for leach lines, but low pressure water drainage.


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