I bought property several years ago and will soon be building our home with myself doing much of the work.  is it possible for me to do the septic or should I hire that out?  Robert F. 

If you are going to install your own septic system you will need to learn 3 things:
· Depth of the seasonal water tables.
· Perk rate of your soil.
· Your state and local code requirements.

The code requirements are easily obtained from your health or zoning office. However I will warn you they are not the easiest documents to translate. The water tables and perk rates are not so easy to get because these tests have to be performed on the property and unless you have done soil borings or perk tests before I would STRONGLY suggest hiring a certified septic designer to perform these tests. This will cost you $200 to $500 but is well worth the investment.

I have seen many times where the homeowner has gone through the time and trouble to install their own septic system only to have the state inspector show up after the job is done and tell them the system is not up to code and it will have to be re-done. Not a fun thing to have happen, particularly when they often will not let them live in the house until the replacement system is installed. Best to have a professional involved that can help prevent these errors.

The soil borings will tell you how deep you can have your drainfield (you will need 3 to 4 feet of dry soil between the bottom of your drainfield and the seasonal water tables) and the perk rate will tell you at what rate the soil will take water (if the soil perks too slow, the home will put out water faster than the soil can accept it causing overloading, if it perks too fast the sewage will not be properly treated). Once you have this information you can get started.

When you know where you are going to install the system stake off the area to prevent heavy equipment from driving over the ground and compacting the soil. I always suggest over-building your system. If you have a 2 bedroom house (the number of bedrooms are what is used to gauge the size of a septic system) you should build the system for 3 bedrooms...3 bedrooms, size it for 4, etc. You will also want to factor in other information into the size of the system, i.e. daycare or beauty salon operating in the home, frequent entertaining, etc.

Before you say this will add a lot of money, understand this, the biggest cost of a septic system is A tank and drainfield, not the size of the tank and drainfield. To increase the size of a system to the next level will usually only add a few hundred dollars.

The minimum size of the tank should be 1,000 gallons, preferably 1,250 or 1,500 gallons. Two 1,000 gallon tanks is even better (the more tank area you have for settling the better). Install an effluent filter in the exit baffle just after setting the tank.

The drainfield should be made up of 4 to 6 legs." Longer shallow trenches are better than short and deep. I prefer trenches be 36" wide and 24" deep, 12" of 3/4" to 1½" rock, 4" PVC distribution pipe with ½" holes, cover the pipe up with 2" of rock, cover with geo-tech fiber (to keep the top soil from filtering down into the drainfield trench), then cover with top soil. The trenches should be 25’ to 100’ long. The bottom of the trench and the pipes should be level or no more than 4" of slope per 100’ (you don’t want the effluent to flow downhill and load up one end). Chambers are also a great alternative to using rock.

If you are on flat land you will want to use a distribution box where the individual lines branch out from. On flat land you will also want to crown the area over the drainfield to divert rain and snow melt.

On sloping land you will want to use a drop box system. This is where the trenches are perpendicular to the slope, when the first trench fills up the effluent spills over to the next trench located 6’ to 10’ further down the hill, then to the next trench and so on.

Note: Many states now require you include an area for the replacement drainfield (when the first one fails) when you design the system. Instead of just designing it on paper, save the (future) higher labor/material costs and put it in now. Then use a diverter valve to switch from one field to the other every few years.

The tank should be a minimum of 10’ from the house and the drainfield should be 100’ away from the well (FHA regulations), 50’ to 75’ away from a body of water and a minimum of 10’ away from lot lines. You also want the tank as shallow as possible for ease of servicing…you do not want to dig 6 feet every time you want to pump/inspect the tank. Of course these guidelines are based on a typical system. If you need an engineered system because you have heavy clay that won’t perk or high water tables you are opening up a whole can of worms.

Find a good designer, have them do the soil tests and get their advice. Also make friends with the local inspector...tell him you want his/her help with your system. If you come across like a know-it-all-jerk he/she will not go out of their way to help you and can make your life a living hell.

At any rate, once you get your system installed make sure you start using it properly. I hope this helps. Let me know what you find out or if you have any other questions...Jim