Locating septic leach lines for construction?

Hi,
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 field.
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 septic system.
I checked out some old NG articles via Google. The best DIY technique seemed to be this one:
http://groups.google.com/groups?hl=en&lr=&ie=UTF-8&selm 970529084301.EAA14024%40ladder02.news.aol.com
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. (LOL)
Now, do septic construction or maintenance companies have other, more reliable tools for doing this?
Thanks much.
- Don
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Don Wallace wrote:

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.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Erma Bombeck said it, the grass is always greener over the septic.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

She was wrong. A properly functioning septic tank does not fertilize the grass over it.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

It is true in my yard but I think it has more to do with water than nutrients. I don't water the grass and it turns brown everywhere else when it is dry.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Bert Byfield wrote:

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.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
While I agree about the brown grass over the septic tank itself, I can locate all my lateral pipe runs in the leach bed by the dark lush green, long grass even in the hottest, driest summer.

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
<snip>

<snip>
In our area, the health department keeps record of septic system installations, even old ones. Worth a phone call...
Paul
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
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
http://www.co.el-dorado.ca.us/emd/envhealth/homeowner_septic.html
Wayne

http://groups.google.com/groups?hl=en&lr=&ie=UTF-8&selm 970529084301.EAA14024%40ladder02.news.aol.com
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
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.

http://groups.google.com/groups?hl=en&lr=&ie=UTF-8&selm 970529084301.EAA14024%40ladder02.news.aol.com
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Eric Tonks wrote:

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.

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

4024%40ladder02.news.aol.com
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Hi,
Thanks, everyone, for the helpful information on locating the septic field.
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 expansion options.
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 pumped periodically.
The size of the present field is no indication ,really, since it was built in prehistoric times as far as today's code goes.
Thanks.
-----------
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

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

HomeOwnersHub.com is a website for homeowners and building and maintenance pros. It is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.