hoshi,
I recently had to have my septic tank system overhauled (replaced the tank and the field lines) so I have learned a little bit about the procedures.
The first thing you need to do is contact your local Department of Health/Sanitation (whatever it is called in your area). Speak with a health inspector and he/she should give you a list of things to do along with the paperwork explaining about the sewage systems, field lines, etc. My health inspector also gave me a list of licensed installers. It had their license numbers, location, things they were approved to work on, and phone numbers. Also available via independent research online was a list of people who had violated the rules and what the violations were. None of the people I called had recent violations.
Something I forgot to mention:
You will need proof of ownership of the property on which you want to install the septic system.. You can either show them the title or you can go to the tax assessor's office for your jurisdiction to get them to print out the info about your property and ownership. It will include the size of the property and location.
This site helps you find the website for the Dept of Health in various areas.
http://www.cdc.gov/mmwr/international/relres.html
But I'm getting ahead of myself. Prior to even looking for an installer, I had to talk to the health inspector about what size tank and field line I would need.
Generally the size of the tank is based on how many rooms the house has (or an estimate of how many gallons of sewage will be processed in a day). For a 3 room home I was advised to get a 1,000gallon tank. So, you need to be able to tell the inspector how many rooms/occupants you expect to have on a regular basis so the amount of sewage output can be determined.
http://www.vdwws.com/faqs/standard-septic-system/ has some info (but it does depend on the rules in your area).
Once the septic tank size has been determined, you will need to do a percolation test on the soil in the area in which you plan to put the leach field. The test may vary depending on your area, but I had to dig some 2ft deep holes that were at least 8 inches wide and fill them with 5 gallons of water the day before the inspector came out. He came out and measured to see how much water was left (if any) and then poured 5 gallons into each hole and came back an hour later to check. From this he determined the perc rate of the soil. This affects how much and what type of leach field you can have.
There are restrictions on leach fields:
They have to be a certain distance away from the property line so that any contaminated soil is not leaching out of your property. They have to be at least 50 feet away from your water source (if you have well water).
The ground cannot have too much of an incline. The lines can't drop more than 12 inches in a 100 foot run.
Lines cannot be more than 100ft in length per run.
If you need to have more than one line, you use a distribution box.
Depending you your soil and such, you may decide to get a mechanical system. Make sure the person you choose is licensed for mechanical systems. If you want one that is non-mechanical, make sure he's licensed for nonmenchanical.
Most of the septic system installers are NOT licensed to do the full plumbing in your house so all they will be able to do is hook it to the existing outlet from the house once a licensed plumber has installed everything.
The septic tank needs to be a minimum of 10 feet from the house (at least in my area that was the rule-- it might be more or less in your area). So when planning out your plumbing system, make sure you plan for that.
Ideally, the installer will do an elevation check and figure out the best place to put the field lines. Keep in mind that the length the inspector will recommend for field line will be based on the pipe and gravel system. If you go with something like Infiltrator Systems it can be shorter. The installer will draw up a plan and send it to the inspector. The inspector will then either approve or reject it. If it is approved, the inspector will issue a permit.
Now, in my case, I was issued a temporary permit (sort of a pre-permit) that I had to show to the potential installers (or read the number out on for them over the phone) after the percolation test. The permit detailed where the lines could be, what size tank could be used, and how much field line needed to be put down. I needed 1,000 gallon and 300ft of line. It ended up being 200ft of Infiltrator system segments.
Things will have to be arranged so that the inspector can come out on the same day as the installation (check local weather forecasts to make sure it isn't supposed to rain). The installer should bring a backhoe to dig the trenches for the field lines as well as the hole for the septic tank. You will want to avoid areas with large trees as the roots can interfere.
Infiltrator segments are 4ft long and 2ft wide. The segments themselves are around $20 each and then there are the end caps that are probably around $15. Apparently in some jurisdictions, the homeowners are allowed to install the infiltrator systems themselves so long as they do it properly and the inspector says it is ok. Your installer will have to be the one to install the tank and hook up the systems to the tank.
My installation ended up costing around $3,400 (not including the cost of having my existing tank drained and removed). I was quoted up to $4,000 for the install by some. I think it depends on the soil type. Too sandy and the soil might collapse. Too rocky and it is hard to dig. Mine was sandy loam that was easy to dig but after a certain point they were afraid they were going to hit water as the sand got whiter.
Anyway, if you want help from people here in the planning, we will need to know the size and shape of the property (perhaps you can provide a sketch?), where the house will be, where any water supply will be, and where you expect to be driving. It is best to NOT drive over the field line as it can compress the soil and decrease the efficiency (or even break the lines). Infiltrator systems can support a small tractor but only if the tractor drives across rather than along it. It has to be covered in 12" of dirt (which is the max amount of coverage allowed on top).
You can plant small shrugs with roots that are not too pervasive somewhat near the field lines and they can actually help to absorb some of the water and make the soil percolate better.
This site has some info on septic systems (I believe it is particularly marketing infiltrator systems).
https://www.thenaturalhome.com/septic.html
Another resource:
http://www.edcgov.us/Government/EMD/EnvironmentalHealth/Homeowner_Manual_Septic_Tanks.aspx
Are you planning to have a water well installed to provide water too? If so, I have a few suggestions on that front.
Please keep us apprised of your progress.
Good luck!
