Working over septic drain field

[Nick_D]

I have a septic drain field which is 2 feet deep, has 12 inches of drain rock with 4" drain pipe in the lower portion of the trench and 12 inchs of native clay in the upper portion of the trench. When I constructed the system last fall, I was able to backfill the trenches without running any equipment ontop of the drain lines. I allowed the drain field to sit for 9 months to allow for some natural compaction from rain.

My question is can I run my BX 2200 over the drain field to complete the finegrading and for mowing. Will the compactive efford made by the tractor degrade the workability of the system?

 

[beenthere]

I can't imagine you would have a problem. If the clay is not wet from the drain field, and the tires don't make depressions in the lawn, then they can't have much, if any depression on the drain field.

If the clay is wet from the drain field, I would not go over it with the BX, and would be concerned that it isn't a good drain field. Can't believe this to be the case though.

 

[cstocks]

I was mowing over my uncle's septic system drain field six months after we put it in. I mow with a NH TC33D and I cannot see where it has hurt it a bit. The soil is mostly sand with some clay.

 

[TimSullivan]

You should have no trouble driving over it. I have cut the new lawn over my drain field and my 4300 with R4 tires does not even raise the new turf.

 

[Hawkflyer]

I have run a B7100 and a B2410 with FEL and backhoe across drainfields with no problem. Both machines had turf-bar tires, and rear fluid fill. I would not recomend that much weight for doing donuts like mowing, but I would think if you take the FEL off, and just have the weight of the machine and mower you should be ok with a BX. Like the other guys here I would not recommend this if the ground is soft or excessivly wet.

 

[upgw]

Nick, I've heard of only one story where a drain field was damaged in this manner, and the guy was running 10 ton cat dozer on top, crushed everything... I think you are safe.

- Patrick

 

[Gary_in_Indiana]

I see this question or something very similar posted fairly often and one thing always comes to mind when I do. In my case my tractor (JD 4200)at it's heaviest (w/ FEL & BH) probably weighs in around 5,000 lbs. I'm not going to have all that weight on one wheel, obviously, so my guess is I have no more than 3,000-3,500 lbs. (one axle or one side) over any actual danger point at any one time.

All of that having been said, I have to wonder if that amount of weight isn't roughly equivalent to just having the whole thing buried just a couple feet or so deeper. I mean, we worry so much about putting too much weight on our tile, septic tank, etc., AFTER we put thousands of pounds of dirt on top of them. Maybe I'm missing something here, but I'd think weight was weight whether it's dirt or iron.

 

[webbmeister]

Gary - all that weight would be cumulative, right? Thousands of pounds of dirt = OK! Add thousands of pounds of tractor = Not OK!?!?

Hmmm ...

Jim

 

[JJT]

Normal sewer and drain pipe has a 3000 PSI crush rating. When I do the math, my L3710 is less than 7 PSI. If the system was installed properly, (pipe backfilled with #2 stone, not boulders), you will not have a problem with a CUT running on top. I'm **** and used ADS' N12, which has a 9000 PSI crush rating, I also did the install so I know it was backfilled with care.

 

[Gary_in_Indiana]

Beats me, Jim. I was just asking. /w3tcompact/icons/smile.gif

 

[webbmeister]

Me too!

 

[Old_Wanker]

It doesnt quite work like that. Theres something called arching that happens after you bury a pipe a certain depth. It means that the weight is born around the pipe and not just down on top of it.

 

[Soundguy]

The reason this is such a problem is US liability lawsuits.... the precast manufacturers won't quote a load carrying spec on the lid of a septic tank. I've argued with them over this quite a bit, even showing them the common sense reasoning.
Even non-reinforced concrete has something between 4-7% ( of compressive str ) before failure..... but people figure it at 0 for safety.
For instance, the precast manufacturer that our company uses plainly states that the septic lids it produces have -no- load carrying capacity. I pointed out that that can't be true, becuase we are backfilling over them with soil.. and that is -some- load. At that point they get irritated and won't talk about it anymore.
Everyone is so afraid of lawsuits.. it is terrible. I have only seen 1 septic tank failure ever. And it was from a pic posted here, of someone using a very large crane style forklift toting roof trusses for a barn or house that was being renovated.
The axle with the most weight ( front ) went through an existing tank lid.

These are extreme circumstances, and a very large load.. much mor ethan we are using with our CUT's etc.

Soundguy

<font color=red>"the whole thing buried just a couple feet or so deeper. I mean, we worry so much about putting too much weight on our tile, septic tank, etc., AFTER we put thousands of pounds of dirt on top of them. Maybe I'm missing something here, but I'd think weight was weight whether it's dirt or iron. "