For many years I was involved in the approval and inspection of septic
systems, the standard systems (drainfields and s-tanks) as well as the
alternative engineered types (pressure dosed, bed systems, etc.)
As a previous fellow stated, the code/standards differ in every state,
county, city, etc. I would add ... the 'soil types' and 'ground water
tables' differ from place to place as well.
Without going in to a great deal of detail, if you are trying to
determine the condition of the existing system there are several
things you can do:
1- go to, or call, the local county/city environmental health
department (they normally permit and inpect these) and give them your
assessor's parcel number (APN) and address, and ask if they have any
files on the property. Many times, depending on the home's age, they
will have permits and/or plans that will tell you where and how big
the system is (tank and drainfields), and when it was installed or
2- ask to talk with the inspector for that area (environmental/health
dept.) and ask him if he can tell you anything about how well systems
perform in the general area.
3-have a qualified septic pumper come out and open up the lids (inlet
and outlet) to the s-tank. The first thing to check when he digs up
and opens the lid is what type of tank is it (reinforced cement or
wood, fiberglass, masonary hand-built, or ?). Then, look at the
bottom of the lid on the inlet side (the side where the pipe from the
house enters). Is there a crud layer caked onto the underside of the
lid??? If there is, then you can reasonably assume that the tank has
been backing up.
NOTE: S-tanks are designed to stay at least 2/3 to 3/4 full of waste
water. This allows a detention time and allows an environment where
the solids will settle out in the first chamber, and time for residual
suspended solids to be digested by bacterial breakdown throughout the
tanks two chambers. The idea is that you have a fairly low suspended
solids content after the w-water leaves the second chamber and travels
out into the underground leechlines.
4- Bear in mind, that current day s-systems are designed to service a
home for about a 25 year period. However, depending on the soil types,
size of home (loading), size of the tank and drainfields, there is an
extremely wide variation in the life cycle. Usually codes require
that when a home is built, the builder/owner must establish an area
sufficient for a 100% expansion area. The expansion area would provide
area for drainfields giving about (on average) a 50 year service life
for the drainfields.
Typically, traditional drainfields fail because the suspended solids
that are carried out of the septic tank are carried into the
drainfields. The SS's are acted on by the aneroebic (without oxygen)
bacteria in the underground rock-drainfield media. A by-product of the
anerobic decomposition of the SS's is metalic sulfides and
polysaccharides. In plain english, these are what you typically smell
when you dig into ocean tidelands... a sulfery smelling stinky black
soil, which seals the outer surface of the rock-soil interface. In
essence this creates a seal for about a 1-foot area in the soil about
the entire surface area of the septic drainfield trenches.
5- I agree with a previous writer who recommended that you provide for
repair in the purchase agreement, etc. I would go a bit further ...
the current owners may never have, and possibly never would experience
a problem with the system. If there are only one or two people in a
home and they are fairly carefull about water, not using dishwashers
and washing lots of clothes, they may never get to a point where they
exceed the capacity of an old s-system and it may continue to work
adequately for years. However, if you move in and, say you have a
larger family, the added load of showers for 4/5 plus clothes washing,
dish washing, etc., and all of a sudden you're facing a $8,000 repair.
So here I would suggest doing your homework regarding permits, getting
free advice from the permit agency people (if they are knowledgable),
and or local septic system pumpers. Then have the system inspected as
a condition of sale and split the cost ... be there when they check
Some folks will 'test' the drainfields capacity to dissapate water by
opening up the outlet side of the tank and placing a water-hose down
into the outlet pipe from the s-tank into the leechfields ... then
turning the water on full blast and let it run for an hour or more. If
water starts to pulse back into the tank, then it is likely that you
will experience failure of the system since it's capacity to dissapate
the water is poor.
Hope this adds some info...
On Mon, 22 Mar 2004 12:50:33 -0600, "Mike Lambert"
Thanks for all the information. It helps to understand the process
before you can look at why it may be bad. I did get a second opinion and
they said just what you wrote. That the build up of suspended solids or
black stuff has caused the field to fail. You were also correct in thinking
that since it is only a 2 person household now without a dishwasher they
haven't had any problems. Since my family is large and we would like to
install a dishwasher it only makes sense to take care of it now. My lawyer
and bank say the seller is responsible for the replacement. The person who
inspected it last also had it pumped and he said it was terrible. Even now
with the cover dug up, there is water above the cover most of the time.
Thanks for helping me realize that this is something I need to take care of
before I buy.
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