Protecting septic lines when driving over them?

[Travis Conner]

What can you do to protect a septic line from vehicle traffic. I want to put another gate in so I can just drive out forwards with a trailer to the street. I don't think the pipe is very deep under ground next to the building, it runs about 150 ft to the septic tank.

[mike stenson]

Don't drive over it.

[Ron Selzer]

big timbers, make a mat like used on construction site

[mike stenson]

big timbers, make a mat like used on construction site

I would say this for a one off. However, it sounds more of a permanent 'solution'. In with case...

[Mark Bolton]

What is "very deep"? Line is running through a yard? Under a driveway? Is this a tank feed? Leach line?

Over thinking an issue?

[Doug Garson]

How about 2" of coarse gravel for drainage and then lay steel grating on top to spread the load from the wheels. You could skip the gravel if the area is well drained. This would be relatively easy to remove if you need to access the pipe.

[Thomas McCurnin]

Unlikely the line as it connects 12-18” from the top of the tank. Above the tank, another 12” is the door shaft.

You’re in more danger of driving over and damaging the doors and tank, not the lines. You should have a map of the tank, doors and lines and their depth. It’s the law here and a punch list escrow item that you’ve received it. If not, it’s a good idea to figure it out now. Most plumbers will recommend digging up and cleaning pumping solid waste every 3-5 years. So I’m surprised you don’t already know what’s under ground unless you haven’t serviced the tank.

Call your plumber.

[Travis Conner]

I know where the tank and the line that feeds it is. I need to open the clean out port to see how deep it is. I forgot exactly.

[Steve Demuth]

What can you do to protect a septic line from vehicle traffic. I want to put another gate in so I can just drive out forwards with a trailer to the street. I don't think the pipe is very deep under ground next to the building, it runs about 150 ft to the septic tank.

If it's a properly installed, reasonably modern line it's deep enough and strong enough that you can drive over it very safely unless the ground has been almost literally liquefied by rain. I did a quick calculation, and Schedule 40 PVC 4" diameter (which is what mine is), at 1' depth, assuming the absolute minimum support from soil (that is, buried in sugar sand), still comes in at barely half the allowed deflection for burial under a Hiway. It wouldn't even be close in compacted soil with any structure.

[roger wiegand]

Anyone ever broken a line by driving over it? In my family's business we had a line (4"PVC down about 2 ft) that had ~5000 cars drive over it every year for 40 years without ill effect. I've driven over our septic lines with my 25000 lb truck and trailer any number of times without an issue. I'd actually be shocked if I broke one that way, never occurred to me to worry about it.

[Adam Grund]

I've driven over our septic lines with my 25000 lb truck and trailer any number of times without an issue. I'd actually be shocked if I broke one that way, never occurred to me to worry about it.

That eases my mind a little. I have always been taught not to drive over it, but do a couple times a year due to it currently being the easiest route to transport firewood to the boiler. Every time I do I cross my fingers, and I’m nowhere near that weight. 7 for the truck and maybe 2 for the trailer.

[Steve Demuth]

Anyone ever broken a line by driving over it? In my family's business we had a line (4"PVC down about 2 ft) that had ~5000 cars drive over it every year for 40 years without ill effect. I've driven over our septic lines with my 25000 lb truck and trailer any number of times without an issue. I'd actually be shocked if I broke one that way, never occurred to me to worry about it.

I agree. I did the calculation mostly because I was interested in just what engineering margin there was.

[Bill Dufour]

Make a concrete road over it. But do not dig too deep and over compact the gravel base. maybe you can find some broken concrete slabs and lay them over the line where the tires go.
Bil lD

[Travis Conner]

I can get some railroad ties and just butt them right together then put some dirt around the perimeter so it will be like a 6" raised pad. All i'm doing is driving directly across the pipe so they should spread the load just fine.

[Thomas McCurnin]

Unless the OP knows exactly where the tank, the lines and the doors are, I would not pave over the tank and leech field. We have a map which says "x" feet from this point is the door and "x" feet is the other door. These things have to be dug up every few years and serviced. I would not to add to the labor cost the cost of jack hammering concrete where the lines and doors are. That was my point to Travis about getting a map, and if he doesn't have one, time to create one. It really is essential, like having a table of the circuits inside your service panel.

[Lee Schierer]

When we had our new sewer system put in several dump trucks trucks drove over the 4" pvc downspout drain lines that were buried at least 24" below the surface in heavy clay soil. They completely flattened both lines they drove over. and I had to replace them. I would suspect that if you drive over the lines a lot you could have the same problem even with a smaller vehicle. It may depend heavily, no pun intended, on how much weight, how often, how deep the lines are and the type of soil.

[roger wiegand]

In our jurisdiction you can't pave over any part of your septic system unless the system has been engineered for it (ie with an engineer's stamp on the plan) and approved by the Board of Health. AFAIK they never approve anything covering the leach field.

[glenn bradley]

they never approve anything covering the leach field.

Open ground (preferably with grass) is part of the design. You could convert to seep tanks (dry well). This is what gave me room to plan the new shop.

[Al Launier]

If your tank has a metal handle you could buy/rent a metal detector to locate it, especially if you already have an idea where it is.

[Thomas McCurnin]

+1 as to what Roger said. One does not pave over a septic tank or the leech field.

[Travis Conner]

I didnt know the septic tank could be so far away from the house. It's like 150ft. I know it has to be 100ft from the well though.

[Travis Conner]

If your tank has a metal handle you could buy/rent a metal detector to locate it, especially if you already have an idea where it is.

I know where the tank is. My concern is the feed line.

[Ken Combs]

JMHO, it your line is sched 40 pvc, or better, and the soil is firm enough that the load doesn't leave ruts, it should be no issue. But , don't do that when the soil is wet enough that it could leave deep tracks.

Way back when, I had a D7 Cat drive across my tank and laterals! No damage. The wonders of spreading the weight over all that tracked area.

Edit to add: there are some products available that look like big honeycombs. Maybe 4-6"thick. It is lain with the cells vertical, filled with soil or gravel and seeded. Looks like lawn, allows water to soak down and evaporate up, and prevents wheels from sinking.

[Perry Hilbert Jr]

My father in law needed to install a some times camper pathway over some lines in his yard. His lines were already below frost line I think there, 30 inches. He got some military surplus grid of some kind.Sort of like some storm drain grates are made of. (vertical width galvanized bars about inch high, perhaps 1/4 inch thick clipped together an inch apart in a grate). he pulled up the sod about three feet long crossing over the lines and then put down the grid and then filled it in with sand and sifted soil and planted grass seed . Once the grass grew up through it, the grate could not even be seen. The US park service uses a concrete grid in the road side pull offs along the Baltimore Washington Parkway that allow the same fill in with dirt and permit the grass to grow. It looks a bit like a bunch of upside down solo cups of hardened concrete.

[Tom Bender]

Houston, water table, no frost line,,,,nope I can't guess what conditions you have.

[Steve Demuth]

JMHO, it your line is sched 40 pvc, or better, and the soil is firm enough that the load doesn't leave ruts, it should be no issue. But , don't do that when the soil is wet enough that it could leave deep tracks.

Way back when, I had a D7 Cat drive across my tank and laterals! No damage. The wonders of spreading the weight over all that tracked area.


The drain fields for both our septic systems are out in pastures. I drive over them all the time with a tractor and brush mower. Never really thought about it that much, other than to not do it when the ground is soft (but I wouldn't be out in the pasture with a tractor then anyway), but I've been driving over one of them for 25 years now.