Locating septic tank

Discussion in 'Toilet Forum discussions' started by mariner, May 7, 2006.

  1. mariner

    mariner New Member

    Messages:
    38
    Location:
    Hixon, BC
    Hi everyone,

    I am in a bit of a dilema trying to locate the house septic tank, without digging up all of the yard area.

    I bought an older home last year and would like to pump out and service the septic tank soon. The previous owners did nothing to their system in all the years they lived here because they never had a problem. I don't have a problem yet, however I need to find the tank. There are no manholes or covers outside indicating it's position. I have located the sewer line leaving the basement and am using 10ft out as a starting point. I have dug down 3 -4 ft and see no sign of the tank or any sign of the main pipe.

    Is there a rule of thumb used to place the septic tank in relation to the house. The system I have has a drain field some 50 yds away from the house, down a gentle slope (probably about 6-8ft difference in elevation). The reason I am looking close to the house is that it would be avantageous to have the tank as close as possible to reduce blockages due to solids, in the pipe. Less distance for the waste to go to the tank must be better.

    Anyone have ideas that might help? Seems I goofed when I bought this place without a septic system inspection!!! Hopefully someone else can learn from my mistake.

    TIA,

    Mariner
  2. Bob NH

    Bob NH In the Trades

    Messages:
    3,317
    Location:
    New Hampshire
    Probe for it

    http://www.fcs.uga.edu/pubs/current/C819-2.html

    The top of the septic tank is probably about 1 to 2 feet higher than the outlet of your drain from the house. It will have a concrete top and probably be at least 6 ft diameter. If you lay out a 3.5ft x 3.5ft grid and probe at the intersections, you should find the septic tank.

    Get a 3/8" steel rod and put a point on it, and probe around near the leach field, toward the house.

    After you hit a hard point that you suspect is the tank, you can probe around to get the shape of it to verify wht you have found. That way you can avoid digging up rocks that are too small to be a septic tank.

    Since the leach field is 6 to 8 ft below the house and sloping away, it is likely that the septic tank is close to the leach field. That is especially the case if you have a drain that leaves the house well below the earth surface at your foundation. The top is usually within 2 ft of the surface; often closer.

    If you have or can borrow a metal detector, you might be able to find the tank by looking for metal. It should at least have a steel handle in the lid, and maybe reinforcing steel in the top.
  3. hj

    hj Moderator & Master Plumber Staff Member

    Messages:
    26,641
    Location:
    Cave Creek, Arizona
    tank

    Most modern tanks will be about 10' long by 4'-5' wide. Your county health or building department, or whoever issues permits for septic tanks in your area, may have a map of your tank from when the house was built.
  4. abikerboy

    abikerboy DIY Senior Member

    Messages:
    202
    Location:
    VA
    When trying to locate mine, the county map was way off, showing the tank at the other side of the yard from where is actually is. We found it with a metal detector, and it was located 138 feet from the house. Upon building my house, I reused the original tank, and the guy with the metal detector located it first by following the cast iron sewer line, then he was able to pick up the rebar in the tank surface. Seems like another thing that you could do is to snake the main line from a cleaanout. When the snake stops against something solid, mark where it stops, and lay the snake out on top of the ground. You should be able to feel any cgange of direction in the line as you push the snake through. Probably wont be exact, but could give you an idea how far away from the house it is.
    Rob
  5. plumber1

    plumber1 Plumber

    Messages:
    1,423
    Location:
    Florida
    septic tank?

    Witch it. You could take two coat hangers and make them straight. Then make them 30" or so long and then put a 90 degree bend about 6" from the end.

    Pick them up with one in each hand. Hold them loosely and put the knuckles of both hands together and point the wires straight ahead and walk forward 90 degrees to where you think the sewer line is. Hangers should spread apart when over the sewer. Keep making passes till till they don't open and that should be where the tank is.
  6. prashster

    prashster New Member

    Messages:
    941
    How old is the house? Your township construc. office should have a map of exactly where it is.

    As far as rule of thumb for distance fm the house, health trumps blockage minimization... The tank is required to be a minimum distance from the house. I think it's 10 feet or more in my area. Large trees, water piping, and driveways also have clearance reqmts, so, the tank could be quite far from the house.
    Last edited: May 8, 2006
  7. hj

    hj Moderator & Master Plumber Staff Member

    Messages:
    26,641
    Location:
    Cave Creek, Arizona
    cover

    I have yet to find a septic tank with a manhole cover, unless it was installed after cleaning it at some time, and that is done very, very seldom.
  8. prashster

    prashster New Member

    Messages:
    941
    My brand new septic tank has a manhole cover.

    Even if older systems don't have a cover, they'd have to have some kind of access for pumping them out. Whether or not it's visible, overgrown, or buried is another issue. I believe you're better off combing through your grass and brush for a cover or pipe than you are randomly digging for the tank itself.

    (I'm not a pro)

    This might be helpful...

    http://www.laundry-alternative.com/locating_septic_tank.htm
    Last edited: May 8, 2006
  9. Mike50

    Mike50 DIY Senior Member

    Messages:
    699
    Location:
    Southern California
    What do you look for when buying/installing a septic tank?
    Latest technology?
    My home was built in 1977.

    No doubt I will need a new one sometime in the coming years.
  10. plumber1

    plumber1 Plumber

    Messages:
    1,423
    Location:
    Florida
    septic tank

    Around here, very seldom does anyone put a man-hole on a septic tank, unless the tank is deep in the ground.

    There will probably be an access door forward on the top and maybe another one toward the rear.
  11. sendec

    sendec New Member

    Messages:
    10
    Aerator?

    If it has an aerator you could usee one of those thingies utility companies use for locating underground wires.

    If you have a noisy aerator it is a self correcting problem.
  12. mariner

    mariner New Member

    Messages:
    38
    Location:
    Hixon, BC
    Hi all,

    Thanks for the replies so far. After doing quite a bit of unsuccessful digging, I have decided to use one the "full srvice" companies in my area (locate, inspect, design, install etc.). When I looked at the rate for renting a mini excavator for a day and the amount of digging I might do until successful, I decided the service company instead. They will use a transmitter that is flushed down the toilet and follow its progress through the piping underground. Supposedly $150 for the location, which sounds reasonable to me. About $150 to dig down to the tank - that being an average price. The pump out price, I don't know but would guess around $200. So for just over $500 I get the lot done, which is reasonable to me - the mini-ecavator rental was going to be close to $400 for the day (incl. delivery, pickup and taxes) and I would still have to dig and get lucky.

    I will let you know how things turn out - it is booked for first thing Monday morning. Just hope that I don't have to get a new system installed, but until I look into it won't know anything. I sure don't want problems in the middle of the winter when temps are -20 F.

    Again, thanks for all of your suggestions, much appreciated - some I have tried. Will post the results later.

    Mariner
  13. mariner

    mariner New Member

    Messages:
    38
    Location:
    Hixon, BC
    Hi all,

    Thanks for the replies so far. After doing quite a bit of unsuccessful digging, I have decided to use one the "full srvice" companies in my area (locate, inspect, design, install etc.). When I looked at the rate for renting a mini excavator for a day and the amount of digging I might do until successful, I decided to use the service company instead. They will use a transmitter that is flushed down the toilet and follow its progress through the piping underground. Supposedly $150 for the location, which sounds reasonable to me. About $150 to dig down to the tank - that being an average price. The pump out price, I don't know but would guess around $200. So for just over $500 I get the lot done, which is reasonable to me - the mini-ecavator rental was going to be close to $400 for the day (incl. delivery, pickup and taxes) and I would still have to dig and get lucky.

    I will let you know how things turn out - it is booked for first thing Monday morning. Just hope that I don't have to get a new system installed, but until I look into it won't know anything. I sure don't want problems in the middle of the winter when temps are -20 F.

    Again, thanks for all of your suggestions, much appreciated - some I have tried. Will post the results later.

    Mariner
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