The grass is always greener over the leach field

July 28, 2007 11:29 AM

How do I find my septic tank?

Right before we bought the property, the previous owner had to put in a new septic system, which included a pumping station to the (uphill) leach field. That was 5-6 years ago, and we want to get it pumped, but where is it? The pump location is known. There's a concrete pad with a removable lid at ground level. The exit from the house is less known. I assume the tank is between the two.
We have a hand-drawn triangulation map, so I dug there with no success. Tried other possible locations from the vague map- still can't find it. Only going down a foot or two, but still digging up the whole yard will take a while.
How deep do they put these things? How deep should I have to dig to hit the top of it? Will a metal detector find it?

posted by MtDewd to Home & Garden (20 answers total)

If these options don't work it may be necessary to use an electronic detection device with a transmitter that can be flushed down the toilet.

More
posted by interrobang at 11:31 AM on July 28, 2007

Have you tried your town hall? Sometimes the town has better maps of your property. We found our leach field by going to the town hall.
posted by senador at 11:48 AM on July 28, 2007

Depending on your local codes, there may be a map filed with the county or the city that shows the exact location.

I was in the same situation as you. Unfortunately, in my case, the house was built about a year before the filing requirement was implemented.

I can't tell you how I ended up finding it, because I didn't. My house sold before I got to that point, but I did tell the new owners they would need to take of that. My situation wasn't an emergency, I just wanted it cleaned out as a selling point, but it sold anyway.
posted by The Deej at 11:49 AM on July 28, 2007

You could try water witching (google). My grandfather once showed me this technique using a pair of coat hangers bent into an L shape. He held the short end of the L in each hand with the long end facing straight forward. He walked slowly around the yard. When he reached our suspected sinkhole the ends of the hangers met. This is not a scientific method, but there seems to be plenty of anecdotal evidence. Maybe it's worth a shot.
posted by reeddavid at 12:12 PM on July 28, 2007

Best answer: Rather than digging, common practice is to use a thin metal rod (I've used a piece of rebar successfully, but in clay soils something much finer, like even a coat hanger may work better) to push down into the ground. Work a three foot by three foot grid patiently, starting in the most likely areas, and you'll probably find it in a few hours. You'll feel the flat concrete top of the septic tank solidly, and at a uniform depth for probe attempts within a few feet of each other, when you hit it. With a few additional "guesstimate" probes holes, you can quickly map out and mark the tank dimensions on the ground.
posted by paulsc at 12:18 PM on July 28, 2007 [1 favorite]

Some company - probably local - installed the previous owners' tank. If you can't summon up sufficient faith* to make dowsing effective, try the yellow pages. Perhaps the installer kept a record of where it is.
*We had friends who owned a plumbing company. The dad was the only one who could dowse underground water. The sons scoffed, but relied on dad and his branched stick or coat hangers.
posted by Cranberry at 1:42 PM on July 28, 2007

common practice is to use a thin metal rod

This is what was done when we had our septic system inspected recently. It took them very little time to find everything, too.
posted by kmennie at 1:42 PM on July 28, 2007

What paulsc said. That's what my parents had me do when they wanted to find it. So, if you have a child to assign the job to, so much the better.
posted by sciurus at 1:43 PM on July 28, 2007

Response by poster: Thanks, all. A friend said she had the electronic device flushed down the toilet done, but that seemed like it would be too expensive. I hadn't thought of the town clerk- I'll try that Monday if I don't find it tomorrow. I have the blueprints of the proposed system, but it's obviously not what was built. I hadn't thought of a dowser either- and there are some around here. I don't believe in that stuff, but if it works...
I hadn't thought a coat hanger would be strong enough (and I had tried a long screwdriver, but not long enough), but I may have something along those lines.
posted by MtDewd at 2:07 PM on July 28, 2007

I noticed iron rings (for lifting up the lid) on the septic tank at my parents house. Mind you, this was overseas ... but if your septic tank is similarly set up, a metal detector could come in handy.
posted by Xere at 2:45 PM on July 28, 2007

piano wire works better than a coat hanger.
posted by MonkeySaltedNuts at 4:46 PM on July 28, 2007

You're in Vermont?

Just wait until late next winter. Look for the first spot in the yard where the snow has melted. That's where your septic tank is. As the old saying goes, the grass is always greener over the septic tank, but that's because the tank generates a little warmth and so, in that spot, the snow melts first and the grass greens up first.
posted by beagle at 5:20 PM on July 28, 2007 [1 favorite]

Maybe it's worth a shot.

It's not.
posted by John Kenneth Fisher at 7:55 PM on July 28, 2007

Please don't pay for dowsing. Please.

You could also look for the cleanout access. It might be sticking above ground somewhere. In my aforementioned house, it was above ground when I first saw the house, but the owner's dogs were chewing at it, so she cut it off, capped it and buried it, and I could never find it again.
posted by The Deej at 8:57 PM on July 28, 2007

she cut it off, capped it and buried it, and I could never find it again.

Not that this is necessarily helpful, but I had a sewer line cleanout that I couldn't find (in fact, I assumed it didn't exist) and so had the line cleaned using half a blade through the front bathroom vent line.

Then one day I had a pile of, er, tissues and whatnot on my lawn -- I'd been cutting the driveway corner too tight for months and (apparently) driving over the sewer access cap (which was buring a few inches under the dirt) sufficiently to crack it, and so when it backed up, out popped, er, tissues and whatnot.

I'm not recommending driving around on your lawn as a way to find your sewer cleanout access, however.
posted by davejay at 11:04 PM on July 28, 2007

Make a pair of coathanger dowsing rods, then use them the way paulsc suggested. Using them the way reeddavid suggested won't tell you anything you don't already know.
posted by flabdablet at 1:53 AM on July 29, 2007 [1 favorite]

Maybe I should've de-emphasised 'thin.' The thing the inspector used was thick and weighty enough to be thrown down at and in to the (rather damp) ground. It looked almost like a fun thing to do.
posted by kmennie at 2:17 AM on July 29, 2007

Response by poster: Eureka! (Or in this case you-reek-a?)
Used a 6' metal rod about 3/16" thick with vise-grips to help push. It was almost 3' down. Found the sides 1st, then dug in the middle for the cover.

You're in Vermont?- I think that was part of my problems- it was deeper than I expected, probably due to the frost line. Also I kept hitting field stones (only about 3 or 4 hundred) and thinking it was the lid. And I didn't have time to 'wait until late next winter... where the snow has melted.' (known here as May).

Thanks again!
posted by MtDewd at 9:47 AM on July 29, 2007

Yay, congrats! Now draw a diagram with measurements on the basement wall with paint.
posted by The Deej at 9:58 AM on July 29, 2007

Response by poster: When it's filled back in, we're going to put some outdoor artwork we have over the spot.
posted by MtDewd at 5:18 AM on July 30, 2007