My wife and I are considering construction of a two car detached
garage in our backyard. Our septic system is also in the backyard. I
*THINK* the new garage could be located such that it would not
interfere with the septic system. I think.
Our lot is only 1/2 acre and the way the lot lines are located and the
way the house is situated, there is only one reasonable place to
locate the garage, which puts it at least on the border of the septic
The house is old construction, 50 years old, and has the original
septic system (which was pronounced in good shape by the guys who
pumped it out last spring.) So my guess is that maps, plans, etc as
well as the original plumber or septic company are loooong since gone.
Last thing I want to do is to trash out the leach field by
construction so that we are in for another $7-$8K in redoing the
I checked out some old NG articles via Google. The best DIY technique
seemed to be this one:
Another guy in this thread suggested flushing barium enema down the
toilet and using a geiger counter to find the lines, but somehow, I
don't think I want to deal with Homeland Security's guys on this one.
Now, do septic construction or maintenance companies have other, more
reliable tools for doing this?
Do you have the original plot plans for the property? If not, go to your
local building department and get a set from them, or at least inspect them.
The plot plan should have the location of the septic tank and fields.
While you are there, ask about setbacks from property lines, septic
tank, and fields.
I can locate my septic tank in winter and summer.
In the winter, the snow melts over it before any other place, leaving a
bare spot when there is 6" of snow all around it.
In the summer, during a drought, or periods of dry weather, the grass
over it dies before any other place. Additionally, I can locate all my
fields by the brown grass over each length of pipe.
Where I used to live the building department had a folder with a few dozen
had drawn pieces of paper showing leach fields and septic systems it depends
how rural area you are in someplace have the stuff over a 100 years old!
Never hurts to ask.
That said when I put up a large barn quite a few years ago they did run into
the leach files, simple solution was just to extend it in the other
direction by a like amount . if you are talking about less than 10% I would
go with that solution.
As of where it is located the guys who pumped it out should have a good idea
where it is from experience as all your neighbor probably have fields
similar to yours, ask them to come out an see if they can guestimate it then
start digging and see what you hit. Leach file sis basically a bunch of
perforated pipe with crushed rock etc.. depending on just how the soil is.
This site has a pretty good explanation
You know where the tank is located, so the leach field will be on the far
side of the tank from the house. You know where the garage would be built. I
would start hand digging a line where the footing would be installed on the
side closest to the septic tank. You only need a shovel width or a little
more. Dig down along that line down about a couple of feet lower than the
outlet of your tank. Look for gravel, dark coloured (and smelly) liquid, and
see if you cross or parallel any clay tile pipes where you want to build. If
you locate nothing you should be good to go. If you hit something it will
help you to get a handle on where the drainage pipes run. 50 years ago
septic tanks were quite small compared to today's requirements and so were
the drainage beds, you might be in the clear.
Where I live, the requirements are 100 feet per bedroom. Seems odd that
the number of bedrooms is the basis for the length of leech fields, but
in any case, I have 3 bedrooms which would require 300 feet. I had 400
feet installed. I also have a separate dry well for 'grey water',
Kitchen sink and dishwasher.
Thanks, everyone, for the helpful information on locating the septic
Next big question: a guy I spoke with at the health district office
said that when I build, I need to keep in mind where a replacement
system could possibly go if/when we need one. The present system is 50
years old. We have a 1/2 acre, 100'x200' lot, with no growth or
I understand that the local code specifies 300 "lineal feet" per
bedroom. (does this sound right?) We have 3 bedrooms.
So, what does 900 lineal feet of installed leach line translate into,
square footage wise? The health district guy said this was 7000 to
8000 square feet.
No way! Or, Way?
At that rate, I have no idea where a new system could go here. The big
"incentive" to answer this question for the longer haul is that if a
lot is not large enough for a code compliant system, they will
actually make the homeowner install a sewage holding tank and have it
The size of the present field is no indication ,really, since it was
built in prehistoric times as far as today's code goes.
PS: What I found about my locating-the-field question:
After calling around I found that the only way to determine where the
field was, was by probing for it. So I had a guy from a local septic
construction company come out and *VERY SCIENTIFICALLY* determine
where the leach field was: using a T-handled iron rod with a pointed
end that he drove into the ground until he hit something. :-)
So, the garage we are planning is clear of the field. We have a few
feet around it.
On Sun, 05 Sep 2004 18:01:22 GMT, Don Wallace
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