Septic Tank Driveway

[atgreene]

I don't know if it is heavy duty or not. I don't know how to find out. Any ideas? My cover (round 2 foot) already broke, that is why I just replaced it with a 1/2 thick steel plate. It is buried 18" deep right outside the garage.

Over engineering has crossed my mind more than once. The deeper I dig into, the more I wonder if I'm just paranoid or worry too much. I'm really only worried about the entire tank top collapsing.

If the tank is in a driveway, chances are it is a heavy model made for that. Depends upon the person who had it installed, classic case of you get what you paid for. If they went the cheap route, chances are a lowball contractor would put a cheap tank in.

How thick is the concrete around the lid? 4" or more? How thick was the cover?

Depending upon how good your state is at record keeping there should be what is called an HH 200 form filed at your code enforcement officer. It may or may not state if it was a HD tank. In Maine it would have the septic design on it, the installers name and address and a complete drawing and of the system. The new rules in Maine require me to locate elevations for tanks and what they are (reg. HD, or low). Not all states keep good records, so it may not be an option.

Start with the thickness of the tank's top, we'll go from there.

On edit, went back and saw that you're from TN, I have no idea the codes or rules there, so a CEO may or may not be able to help you.

 

[Pirate]

That lid couldn't have been about 3" thick. I went through all the paperwork for the home but couldn't find anything about the tank. The guy who had it built was a real cheap ******* so I wouldn't count on a reinforced tank.

Edit: Just dug out receipt from builder. 1992. Says 1000 gal septic tank, $337.40. They aren't in business anymore.

 

[atgreene]

That lid couldn't have been about 3" thick. I went through all the paperwork for the home but couldn't find anything about the tank. The guy who had it built was a real cheap ******* so I wouldn't count on a reinforced tank.

Edit: Just dug out receipt from builder. 1992. Says 1000 gal septic tank, $337.40. They aren't in business anymore.

That is telling. A cheap ******* hired a cheap company to do a cheap job and now it may have been done so as to cause a problem down the road, AND, the company is no longer in business. Wow, big suprise.

Sorry for the rant, just tired of the lowball morons who run around and do this sort of thing. When the oil truck crashes through this tank they'll be long gone and the next guy gets stuck with the bill for a shoddy job.

If it has a 3" cover and they paid $337 for it, I doubt it's hd.

On to plan B.

How deep is the tank buried? Is it under the driveway or next to it?

 

[Pirate]

Good news, it is NOT under the main driveway. Real lucky for me as I've had several tandem axle trucks loaded with gravel up here. It is however, right next to the driveway. The tank is about 7 or 8 feet from the entrance of the basement garage. You have to drive over the tank to get into the garage. It is 18" deep.

 

[PILOON]

While not an expert, I have seen excavators drive over tanks all the time.
As I understand it the big issue is pressure points, ie a rock that concentrates pressure on the tank.
The preffered installation method is surounding he tank with sand or fine gravel.
At 18" deep I'd say that your tank could support a considerable load, maybe not a loaded 10 wheeler but a car or pickup for sure.
As to lids, I drive my tractor over mine all the time as it is where I park my CUT and it is exposed (flush with ground) for easy access.
In fact I have also parked my 3/4 ton loaded PU on it more than a few times.

 

[texbaylea]

Check for a Pre-cast concrete company in your area. In this area they make precast concrete decks for bridges. The ones I have seen are about 2.5' wide by various lengths and look like they have longitudinal holes. They may have seconds and discards that the state would not accept. There is not much they can do with these.

You could use a section to bridge over the septic tank.

Vernon

 

[Pirate]

The saga continues. Today I obtained the "official" state of Tennessee certificate which has all of the original septic layout/information. The approving official made a crude drawing and then it says, dimensions not known as excavating and tree removal ongoing. That was it. Approved without having a clue just how close the original owner placed the tank to the house.

I called a local septic expert today. He is coming over to look at what I have. Two options: put in a new tank somewhere else or cap over the tank. We'll see but I'm putting my bet on capping as I don't have much room around here.

 

[orezok]

I wouldn't worry too much about the weight of a concrete slab over the tank. Concrete weighs about 150# per CF, average soil about 100#. Just think about what you weigh standing on a "footprint" of about 1 SF. Engineering wise, load is spread at about a 45 degree angle from the point source. That is a 10,000# dynamic spot load on 1 SF will be reduced to about 1,100# per SF at 1' depth, at a 2' depth, 400# at 2' etc. (see dwg.)

Three foot of dirt cover will span just about anything. We put down 8" aluminum temporary water lines on the ground, cover with 3' of dirt and run fully loaded 657 scrapers over them, 50 tons.

Never crushed one yet.

 

[JB4310]

I wouldn't worry too much about the weight of a concrete slab over the tank. Concrete weighs about 150# per CF, average soil about 100#. Just think about what you weigh standing on a "footprint" of about 1 SF. Engineering wise, load is spread at about a 45 degree angle from the point source. That is a 10,000# dynamic spot load on 1 SF will be reduced to about 1,100# per SF at 1' depth, at a 2' depth, 400# at 2' etc. (see dwg.)

Three foot of dirt cover will span just about anything. We put down 8" aluminum temporary water lines on the ground, cover with 3' of dirt and run fully loaded 657 scrapers over them, 50 tons.

Never crushed one yet.

Interesting, I really wanted to know if there was a formula to determine how the weight would be spread as you got deeper. probably many variables due to soil types? I was thinking if you dug a hole 3 feet down and buried an egg or a soda bottle, you probably could drive over it without it breaking.

Pirate, I think avg dimension of a 1000 gal tank is 4'x8' aprx 4ft deep, typical requirement for a 3 BR + home. You mentioned it's just outside the back garage door, since it sounds like you are determined to do something, while your at it make the slab a little bigger than needed, a little wider than the door and out 15 feet or so. This way you'll have the tank covered and also have a nice concrete pad for use as a patio or working on things etc.
I truly believe you will have no problem pouring it right on the ground, and all you really need is heavy gauge wire mesh like 6"x 6"x6 gauge, as opposed to rebar.

JB.

 

[Pirate]

Well, concrete guy came by. 1500. That with the 300 I have to pay for the cover. 1800.

Tank builder came by. Gave me a great idea on where to just put in a new tank. 500 for new tank.

Now, I have to get the local grading/landscaping guy out to give me his estimate for some backhoe work. Hardest park will be finding where line starts at drain field.

I've been bit in the rear end before with heavy equipment prices so I'll wait to decide.

It's funny, I was dead set on just putting in a slab until the other guy came out. Glad I didn't bet or commit.

 

[plowking]

If your leachfield has a distribution box at the end closest to tank,you can run a snake[plumbers flat steel snake] or camera down the line to find it. If it's not to deep,I run a snake and have customer stand near leachfield to hear the vibration of snake bumping in the d box,if it is too deep I can use a metal detector to follow snake. There are locator devices that can be taped to snake or flushed down toilet to find the tank but these costs extra. If you have the tank in the lawn,a H-10 rated tank should be fine, under driveways still require a H-20 rated tank. I had to go out and pump and inspect inside a tank for damage from a logging truck driving over it,luckily he got the edge and not over the covers,the weak spot is at the seams around the openings. I washed out the tank and used a telescopic inspection mirror with a bright light,no cracks were visible. However the d. box is bad and I have to go back and replace the box,jet the lines and add a leachfield vent,new baffle and filter to update the system. The pipe to the leachfield should be schedule SDR 35 or 40,most likely they used schedule 20 which has a too low crush load. plowking

 

[Pirate]

Well, after even more careful consideration, I and others determined it would be a dumb move to put in a new tank. The system works fine and I don't really have room to easily put in another tank.

I attached a picture of the tank exposed. On the left is the garage door. The guy that put that tank in that spot is a moron.

I still plan on putting a slab over it. I have a price of 1100 for mud work. The two sewer covers with flanges from East Jordan Iron Works are 450 each. This price sucks but I looked all day and couldn't find anything cheaper that can support the weight of vehicles.

I need to do this job unfortunately. I think I found the place that made the tank. I was snooping around today and noticed he didn't use wire in his tanks. I'll post a picture when the job is done.

Oh yeah. I'm going to put a one foot high 30" ring made of galvanized around the septic covers. They will hold back the dirt. On top of them I will use temporary wood shoring to hold up the sewer covers until they are dried into the slab. Once dry, I'll remove the wood.

I found both the environmental certificate and permit for the system. Neither of them matches what I have. They put down a system for 3 bedroom when I have a 5 bed/3 bath. I would have preferred larger system. The permit shows the tank behind the middle of the house with the filed where my driveway is now. The environmental certificate says everything is approximate as excavating and tree removal is ongoing. This is one time I wish the permits and such would have done their job. No wonder he was in a hurry to accept my offer and sell me the house. Shame on me for not knowing enough. This is my first (and hopefully last) septic system.

Funny story. They guy that cleaned off my tank today told me he had a job at a local junk yard. They told him to dig a hole that would fit that an old car. They ran the plumbing line into a window vent and buried it. Instant septic tank.

 

[bearmtnmartin]

why don't you just dig around the tank, make the hole longer one the end away from the house and drag it over 10 feet?. I have done that before a few times. It is easy to do and will cost very little. Tanks are put in the spot that makes great sense at the time, but the homeowner often ends up kicking himself later. When I do a design, I tell the homeowner to think about the location, and tell me where they want it. Then its not me looking silly down the road.

 

[CurlyDave]

This is my first (and hopefully last) septic system...

I don't know about that. Rural living is habit forming. I sure hope I never have to live close enough to other houses to have a city sewer.

Funny story. They guy that cleaned off my tank today told me he had a job at a local junk yard. They told him to dig a hole that would fit that an old car. They ran the plumbing line into a window vent and buried it. Instant septic tank.

This is a traditional redneck septic system. No delivery charge -- just tow it right to where you want it.

 

[JB4310]

[QUOTE
This is a traditional redneck septic system. No delivery charge -- just tow it right to where you want it.[/QUOTE]

Oh Man, I wouldn't want to dig that thing up in the future.

Is that true? people are using old cars as a septic tanks

JB.

 

[Wis Bang]

[QUOTE
This is a traditional redneck septic system. No delivery charge -- just tow it right to where you want it.

Oh Man, I wouldn't want to dig that thing up in the future.

Is that true? people are using old cars as a septic tanks

JB.[/QUOTE]

After high school I worked for a local excavator who collected a septic pumper truck in payment for a debt from a septic guy. He used it for side jobs, mostly on weekends, for cash. His yard was on the edge of town and had a sewer manhole where he would dump the loads...

The worst 'red neck' tank we pumped was a small cottage right next to a stream. It was a heating oil tank placed on it's side w/ a 12" square cutout by the outlet. It was packed solid & we had to spray it w/ a garden hose to get the septic soft enough for the Marlow 'Mud Hog' pump to pull it out. I think he charged the guy $50.00...

Last fall I had the tank under the outhouse @ the cabin pumped. The guy charged $250.00 to do a 1000gal tank [legally] & he had a vacuum pump & sucked up about 20 years of 'deposits' in about 15 min...last five of that was making sure he got the corners...

 

[Pirate]

First picture shows the riser rings I put in. They are those bands that connect galvanized pipe. 12" high. The shop cut off the bolt flanges and then tacked them into 30" round circles for me. 20 bucks each.

Second picture is concrete forms in today. We built those plywood forms to place the sewer covers on top of. There will be 4" concrete on top of the two plywood boxes with the sewer covers.