Drive equipment over septic drainfield?

[Richard]

Scenario:

10 year old house with septic tank/field and buried power line. We're adding onto house and will get too near the existing tank and build OVER the existing power feed.

We need to move both, last week the power feed was rerouted.

Now comes the tank. Builder says he's going to dig to our tank, pump it, fill it with concrete so this will not be a weak spot underground where my extended foundation might force it to settle...

He's going to dig a hole on the same plane as it some feet away, put another tank down there and then feed from house to new tank back to existing field.

I'm on a slight hill with house on the uphill side so the ONLY way they can get to the tank to dig it up, dig new hole and dig trenches to the existing drainfield is to take what ever equipment they use, OVER my existing drain field.

I told my contractor WAY before we signed anything, unequivically that when this time comes, in NO way do I want any heavy equipment driving ON TOP of my drain field.

(truth be told...I think they can squeeze a hoe to the side of it for most of this work)

I told him that a trackhoe would be fine since it was on tracks and not rubber wheels. I also said it was ok if they put planks of plywood down under a wheeled machine to help spread the load out.

Simply put, I did not want the tires of a "X" number of thousand pound machine driving over my drainfield and compressing the soil or the leach things, themselves. I pointed out to him that this would be hidden type of damage and something that "if" it ever created a problem, it might not be for several years and I simply do not want to risk anything to the drain field


Ok, he has since had a septic guy quit bidding on this job once this guy heard my 'demands' that a wheeled machine not be allowed on my drainfield.

Wheeled machine would include a regular backhoe/loader and also the truck that they'd need to bring the new septic tank in on.

Again, I said it was OK to do something like that if we had plywood "road" under the wheels, to help spread the weight.

My contractor said that woudln't work because "the outriggers on the backhoe alone, would punch right through the plywood"

(of course, my initial thought to that was...."you could put THREE or more layesrs under the outriggers", but I didn't say a word)

So...

Am I being on or off base, being so concerned about keeping heavy equipment off my drainfield???

 

[Dirthog]

If the field was put in correct the first time you will have no problem with it! If it has rained for two weeks straight or something like that I would be carefull but that is all after 10 years the ground has settled all it is going to.

 

[rexcramer]

No, you are being reasonable. The key is to keep the wheels off the drain tiles. The area between the tiles can be driven on, if they can be accurately located. That is how the field was made in the firstplace, with a backhoe running between the tiles.

I have ran a large dozer over my field many times with no problems, but i would never run my backhoe over my field.

If you allow the contractor to drive over your field, and some tiles are crushed and your field backs up five years from now, do you REALLY think the contractor will come and fix the field????

While a single piece of plywood will not hold the backhoe stabilizers, a couple pieces together would.

 

[LogChain]

Richard,


You might consider a plastic septic tank. This spring I had installed a 1060 gal Fralo septic tank (FRALO Branded Tanks - Plastic Septic Systems - Roth Global Plastics) and drain field for a guest house in the woods. The tank weighed 520 lbs., cost $900, and has a 50-year warranty (purchased from Blalock's in Seviervlle 865-453-2808). I picked the tank up using only a 4'x8' trailer. The tank was 11' long and 5' diameter--nearly a perfect fit. A mini track excavator (Bobcat) was used to dig the holes for the tank and drain field. Because the tank was so light and made of slippery plastic, I was able to push the tank into the hole without assistance from the excavator. The total installation (including digging and filling 120' of chamber drain field) involved 7 hrs of excavator time and essentially no soil compaction. Just a thought.


LogChain

 

[Matt_W]

I don't know if this helps but I have a sand mound and the inspector said that if there was any evidence of any wheeled vehicle on it. Instantly would
fail.
For the cost of having to do any repairs on that I would try to stay off.

 

[Richard]

Well, I gotta say, I'm glad to hear that my gut feeling seems to be reasonable. I was beginning to think that I was being a bone-head about the issue.

The contractor has another septic guy and we're meeting at the house tonight.

My conscience is clear because I told the contractor more than once that this is an issue for me and one that not only will I not budge on...BUT...that I also intend to be there the day of digging to monitor the situation.

(because of him not finding out how much the electrical was to move, he said he didn't quote me that price and I'd have to pay for that....once I pointed out that I showed him the electrical problem (being located too close to new construction) he didn't remember....finally, I pointed out that this might be a deal breaker and he could tell I was serious)

I say the above because as I made my comments to him about how stern I was on the bid including the electrical work, I think he knows I'm serious about the drainfield issue and he's been bringing that up EARLY in the conversation with a septic guy.

BTW, the electrical feed was moved to go around the other end of the septic drainfield (the long end). They made it probably 200' as a wild guess.

I called the electric company today and found out they only charged $370.00 to do the work. The engineer at the electric company said I'll be one of the last people they do it for that cheaply..., they're stopping the program where they do it for essentially free.

 

[flusher]

Scenario:

.Simply put, I did not want the tires of a "X" number of thousand pound machine driving over my drainfield and compressing the soil or the leach things, themselves. I pointed out to him that this would be hidden type of damage and something that "if" it ever created a problem, it might not be for several years and I simply do not want to risk anything to the drain field


Ok, he has since had a septic guy quit bidding on this job once this guy heard my 'demands' that a wheeled machine not be allowed on my drainfield.

Wheeled machine would include a regular backhoe/loader and also the truck that they'd need to bring the new septic tank in on.

Again, I said it was OK to do something like that if we had plywood "road" under the wheels, to help spread the weight.

My contractor said that woudln't work because "the outriggers on the backhoe alone, would punch right through the plywood"

(of course, my initial thought to that was...."you could put THREE or more layesrs under the outriggers", but I didn't say a word)

So...

Am I being on or off base, being so concerned about keeping heavy equipment off my drainfield???

Here's the TLB my contractor used to put in my septic system 3 years ago. IIRC that CAT TLB weighs over 15,000 lb

My leach line is 100 ft long and lies in a trench 24" wide by 66" deep. The leach field has a nice gravely loam layer about 3 ft below grade that's ideal for septic systems. There's 36 inches of drain rock under the leach line, about 6 inches of rock above the pipe, geotextile and backfill dirt.

Mike, the crew chief and ace TLB operator, carefully backfilled the trench.

I asked him if he could level out the backyard area with that TLB after he was finished with the backfilling.

He drove that big TLB over the leach line several times doing this job with no ill effects that I can detect after 3 years of septic system use.

 

[wedge40]

Richard,


You might consider a plastic septic tank. This spring I had installed a 1060 gal Fralo septic tank (FRALO Branded Tanks - Plastic Septic Systems - Roth Global Plastics) and drain field for a guest house in the woods. The tank weighed 520 lbs., cost $900, and has a 50-year warranty (purchased from Blalock's in Seviervlle 865-453-2808). I picked the tank up using only a 4'x8' trailer. The tank was 11' long and 5' diameter--nearly a perfect fit. A mini track excavator (Bobcat) was used to dig the holes for the tank and drain field. Because the tank was so light and made of slippery plastic, I was able to push the tank into the hole without assistance from the excavator. The total installation (including digging and filling 120' of chamber drain field) involved 7 hrs of excavator time and essentially no soil compaction. Just a thought.


LogChain

Nice concept but wouldnt this be even more fragile than the old fashion cement septci tank. If I used something like this I would figure out a way to mark EXACTLY where the tank and field are located.

Wedge

 

[skipro3]

I don't think driving a rubber tired TLB over an existing 10+ year old leach field is going to make any difference. Think about it; the field drains are probably 6" perf plastic pipe buried at least 2 feet deep. So any pressure on top will be easily distributed by the time the pressure was felt 2 feet down. I bet if you dug a hole, but a min/max scale in the bottom, filled the hole and compacted it, then drove a tractor on top of it that the scale wouldn't change it's reading.

I do know that any portion of the septic and leach field, including the connecting line, can not have vehicle traffic over it as a regular occurance. Meaning, you can't build a driveway or anything of that nature over it. It also needs to be on the original grade of the land. Meaning, it can't be any part of a fill or even a graded down area. It's important that a perk done is indicitive of the drainage of the field. A cut pad for the field isn't 2 feet deep for the lines any more, it's 2 feet PLUS what ever the cut was. At least all this is true in California in my county. I just went through all this. Also, the tank can be installed in fill and doesn't need to be set into the natural grade of the soil surrounding. My tank and field was dug and set by an independant heavy equipment operator. It cost me a total of $12,000 including the tank, lines, permits, perk test and the engineer wet stamp on the plan. We have VERY rocky soil but it sure perked good. Good drainage.

But when it's all said and done, it's you land, your dollars and your decision that matter. Just be aware that it just might cost you to be a little paranoid! Ha! Good luck and he's to coming out smelling like a rose!! Cheers!

 

[Richard]

My leach line is 100 ft long and lies in a trench 24" wide by 66" deep.

Is that pipe that appears to be a PVC type pipe, your leach pipe? (or what ever they're called)

If memory serves me, my leach pipe is 6" or 10" diamater and looks more like insulated "ductwork" that would be inside your home (if in error, realize this is 10 year memory of a 3 hour event while I was on site)

I'd not be worried about driving over 'hard' piping....it's this soft squishy kind of tubing that I'm worried about crushing

Now I'm beginning to wonder if my memory is correct on the type of pipe they put in the ground

I don't mind being a hiney head, but I don't want to be one when I'm in the wrong.