Septic System

Discussion in 'Plumbing Forum, Professional & DIY Advice' started by missy, Jan 25, 2006.

  1. missy

    missy New Member

    Messages:
    2
    I hope that someone can help me. I am installing a septic system for the first time. I have a 1000 gallon concrete tank already in the ground and the pipe running from the house to inside the tank but need some help. I have the washed rock under the piped coming out of the house, Can I just cover it up with the dirt now? Also I need to know how wide and deep the leach lines need to be? How much rock needs to go under the pipe first in the lines with the pipe sitting on top of them? Will plastic be fine on top of the holed pipe and then the dirt? Hope that someone understands my questions and can help. Also what machine is best to dig the leach lines? Thanks :confused:
  2. plumber1

    plumber1 Plumber

    Messages:
    1,423
    Location:
    Florida
    Guess she needs someone to explain how to install a field bed.
  3. Bob NH

    Bob NH In the Trades

    Messages:
    3,317
    Location:
    New Hampshire
    You must be out in the countryside somewhere to be able to put in a septic system without having the design approved. You can get some help, but more information is required. Take a look at the web sites at the links below.

    http://www.co.el-dorado.ca.us/emd/envhealth/homeowner_septic.html
    http://www.ext.vt.edu/pubs/envirohort/426-617/426-617.html
    http://webpages.csus.edu/~sac66230/septicpage.htm

    Do you have a percolation test (usually just called a "perc test") to find out how fast the water will be absorbed? That will affect how much treanch area you need.

    What are the slopes and elevations relative to the house and how far are your from your well and from streams and other drainage systems?

    Take a look at what is here and come back with another post.
  4. missy

    missy New Member

    Messages:
    2
    Yes I do live way out in the country but I did have to have a permit that my mother got for me but she is ill now and can not find it but remembers certain things that needs to be done. The things that I mentioned in the first post is where I am at in the process and so confused. She was able to tell me that the lines had to be anywhere from 80-100' long with four coming out of the distribution box. I have no well I have city water and there is a creek about 1500 feet from the house. The slope will probably be too much for the drainage but it will have to be leveled out. But the other question that I had was how much rock do you have to put under the pipe? I know that from what I have read that it also has to cover the pipe. Thanks
  5. Gary Swart

    Gary Swart In the Trades

    Messages:
    7,395
    Location:
    Yakima WA
    :( With all due respect, you should have this job designed and installed by professionals. As already pointed out, there are many things that have to be taken into consideration, and since local conditions and requirements can vary a great deal, you be headed to real problems.
  6. Bob NH

    Bob NH In the Trades

    Messages:
    3,317
    Location:
    New Hampshire
    The third link in my first reply gives you the best detail of what you need. Find the pictures labeled "Distribution box and large trench details" and Details of leach field trench dimensions and components. They specify 6" of stone below the pipe and 2" of cover, which gives you a total of 12" to 13 " with 4" pipe.

    The easiest way to dig the trench is with a bulldozer. For your four pipe system you would need a trench 20 ft wide. A bulldozer will make that quite quickly if you don't have immovable rocks. The downside of that approach is that it will require about 80 cubic yards of stone; probably about 120 tons if they sell it that way. That calculation is based on 13" of stone. Cost of stone is usually a big expense. Try to get prices on crushed stone and on washed and screened natural stone.

    If you use the system with separate trenches, and make them only 18 inches wide, you would need only 24 yards of stone. The trenches could be dug with a small backhoe.

    Digging trenches 5 ft apart is tricky because the machine may run over into or collapse the adjacent trench. It is also difficult to fill the inside trenches without a bucket loader. That is too much stone for a wheelbarrow. I guess you could fill the outer trenches first and drive over them but it is not a good idea to pack them down too much.

    Leach field trenches and pipes are different from sewer drains in that the trench should be almost level. The MAXIMUM slope for the pipes must not exceed 1/4" for every 10 feet. You want the water to stand in the pipes while it drains out or you will lose the effectiveness of the uphill pipes. That is a condition that can usually be achieved only with a surveying type instrument or with very careful leveling with a good level attached to a 10 ft 2x4 and adjusted to be precise. You will not get the backhoe operator to do that and it may require some hand work. You will also have to do a good leveling job with the pipe. The best solution is to put stakes in the ground with an instrument and work from them.

    Automatic levels are very easy to use if you can borrow one. I bought one on E Bay for $100 but you also need a tripod and something to use for a level rod. If you can borrow one from a builder or construction friend they will have a tripod and rod.

    It would help to know how much of this work you intend to do personally to get some idea about issues of staging machinery. If you hire it done they will come in with a bulldozer and crew and do it all in one day. If you are doing the physical labor you will need to plan on getting equipment to dig the trenches, spread the stone, and backfill with stone and fill after you are done.

    If you have access to a small farm tractor with a backhoe and bucket, and are doing it yourself, you could do it one trench at a time. If you have to rent equipment or hire people to come in several times it will probably cost less to hire the whole job done.
  7. hj

    hj Moderator & Master Plumber Staff Member

    Messages:
    27,242
    Location:
    Cave Creek, Arizona
    tank

    Regardless of what we tell you, based on our experience and your postings, unless it is done at least to the minimum that the permit called for, you will be rejected and have to modify or redo the system. Call the governing body and get a copy of the permit.
  8. Cass

    Cass Plumber

    Messages:
    5,980
    Location:
    Ohio
    I would suggest that you have a talk with the health dept about what you need to do. You could end up spending a lot of time, energy, and $$$ just to find that you have to rip out every thing you did.

    Being 1500' from a creek may require you to have a special system.
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