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Home Buyer's Basic Guide to Septic Systems Easy Guide to Inspection & Testing When Buying a Home With a Septic Tank
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Advice for Home Buyers who are buying a property with a private septic system. In order to help buyers obtain Information that addresses these concerns. We have put
together this guide to help in making informed decisions regarding
the potential problems and costs associated with a property's septic system. This document gives a simple overview of the questions to ask and tests
and inspections to order if you are buying a property with a septic
system.
If you don't really want to know much about septic systems but you want to know how to inspect and test
this costly and buried system when you're buying a property with a septic system, septic tank, septic fields, then read
this document.
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Basic Advice on Buying a House with a Septic System
Frequently prospective buyers of a single family home have many questions
regarding the septic system serving the dwelling:
What does the existing septic
system consist of?
Are the septic system tank, piping, drainfield and other components working property or do I face significant costs or perhaps unsafe or unsanitary conditions that have not yet been disclosed?
What septic inspections and tests should I have performed when I am buying a home?
How long will a septic system last?
If you prefer a complete, detailed guide to how to determine the condition of a septic tank, drainfield, leach field, soakaway bed, piping, etc. before buying or selling a home, see our buyer's guide to septic systems beginning at HOME BUYERS GUIDE to SEPTIC SYSTEMS.
If you need to know still more about septic system components,
septic system maintenance (such as tank pumping and septic additives),
or details about septic system inspection, diagnosis, repair, and
alternative septic designs, Our main septic website page provides in-depth articles about these topics.
Components of a Septic System
In simplest terms, a septic system consists of a holding tank which
retains solid waste and grease from household waste water, and an absorption
system or "leach field" which disposes of liquid wastewater or "effluent" which
leaves the septic tank for absorption below ground into soils at the property.
How to Inspect and Test a Septic System When Buying A Home
Why inspect and test a septic system before buying a home?
The septic system is a relatively expensive and buried system which
does not have an infinite life. Eventually drain fields fail and sometimes
septic tanks, especially steel ones, rust out and need replacement. Also,
old septic tanks, cesspools, and drywells, especially site-built or "home made" systems
and systems in certain soils, can collapse, forming a very dangerous site hazard.
While no septic inspection and test can guarantee 100% that all septic defects
have been found, properly conducted, these procedures can reduce the chances
of a dangerous or costly surprise at your new home.
Septic Inspection and Testing for Home Buyers, Step-by-Step
You can do steps 1 and 2 yourself. If you hire an expert to inspect and test the
system (some home inspectors can provide this service), the inspector will also perform step
2 and 3.
Basic Questions:Ask the seller the following questions. Don't worry if the seller says they don't know the answers. "Not knowing" is also important information.
These questions are deliberately a bit vague in order to allow people to tell you whatever they know rather than cutting off or suggesting answers.
Convey the answers to these questions to your septic test consultant.
How old is the property?
Is the property occupied or vacant? If occupied, for how long and by how many occupants? If vacant, for how long?
How long has the seller owned the property?
Where is the septic system?
What is installed?
What is the service or repair history of the septic system?
When was the tank last pumped? [Warning: if the seller offers to "have the tank pumped for you" ask them not to do you
that favor before your inspection as pumping the tank prevents testing the drain field.]
Visual Inspection: Make a visual inspection of the property. Look for wet areas, smelly areas, rocky areas, areas of recent excavation.
Also make note of the location of and distance to nearby streams, private wells, ponds, buildings, property lines, and rocky areas, and areas
of trees and shrubbery.
[Warning: be very alert for evidence of sink holes or subsidence. Do not walk over anything suspicious as you might step into or fall
into a collapsing system.]
Septic Loading & Dye Test: Hire a septic test consultant to perform a septic loading and dye test. This procedure puts a test volume of water into the
system to look for evidence of a blocked pipe or for breakout of septic effluent at the yard surface - indications of the need for repair.
If you are looking at a completely new home and septic system you might omit this test but don't assume that new systems are immune to
failures.
Pipes settle and break or systems can be improperly installed. If the tank was pumped immediately before your inspection
you should be suspicious, and you might defer the loading and dye test as it may be unable to put enough water into the system to
test the drain fields. The dye itself is just a coloring agent to identify water that may appear at the yard surface. It's the test volume
of water that's important.
Pump and inspect the septic tank: this step may or may not be necessary, depending on the age and service history of the system
and the results of the visual inspection and loading and dye test. Important additional information, available when the tank is pumped,
can tell you if it was past-due for pumping (risking damaging the drain fields) and if it is damaged. You'll also know exactly where the tank
is, if it's concrete, steel, fiberglass or home made, if it has been damaged, and if it has a save cover.
Additional steps which are not normally done but which may be performed if there is evidence of system damage or failure are listed next. These steps would ordinarily be
performed by a septic contractor who installs or repairs septic systems. Some septic pumping companies also perform septic repairs and field
investigations. A septic engineer may be needed if you are expanding a system or if you require design to repair a system on a difficult site.
Find and Open the Distribution Box which connects the pipe from the tank to the network of drainfield lines.
Excavate suspicious areas such as wet areas at in the leach field, subsidence areas.
Perform soil percolation tests or "Perc tests" to evaluate the ability of the soils to absorb effluent. This involves digging
a hole, pouring in water, and measuring the time for a given volume of water to be absorbed into a given square foot area of soil.
Soil & Site Research to include determination of the soil quality, the depth of the seasonal high water table in the
ground below the leach area, etc. - this work may be needed if a system is to be replaced or relocated, especially at a difficult site.
More Reading about Septic System Inspection and Testing
More basic information about how septic systems work is in this document after this section. More in-depth
information about the steps in the procedure outlined above can be read at the following online articles:
For a leaching system to function properly it must:
Provide enough application area. The application area is the amount of
surface area of soil within the leaching system where sewage effluent is
applied (referred to as "wetted" area). The amount of application area needed
for a given house depends on the characteristics of the soils on the property
and the daily flows (in gallons) generated from the house.
Be surrounded by natural soil conditions which will be able to dissipate
and disperse the discharge without becoming over saturated.
Provide enough capacity to store effluent during periods of unusually heavy
use or when rainfall or subsurface flooding reduces the ability of the system
to disperse the liquid. Note: Curtain drains or ground water interceptor
drains are sometimes installed upgrade of the leaching system to minimize high
ground water conditions.
It is important to realize that, once a septic system has been installed, only one of
the above factors can be controlled by the homeowner. The homeowner can control
how much water is actually being discharged to the system. Since each system
has a set maximum capacity, it behooves the homeowner not to exceed that
amount.
Signs of Trouble With the Septic System
If a system starts to experience difficulties, what are some of the common symptoms?
Plumbing fixtures may exhibit difficulty in releasing their contents
(slow draining, bubbling, backups, etc.). This condition may be
system-related but it could also indicate just a clog in the interior
piping or sewer line.
You should have the interior piping checked before
proceeding with an investigation of the sewage disposal system.
[DJF added: See CLOGGED DRAIN DIAGNOSIS & REPAIR]
Large volume discharges (such as, washing machines, dishwashers and
bathtubs) cause either a backup, as noted above, or, an overflow of sewage
above the septic tank or leaching field. If this condition is usually at
its worst during and/or directly following a heavy rain event, then the
septic system is indeed suspect.
If backup alone occurs independent of wet
weather, you might first check for a partial blockage of the main drain that
has occurred some distance from the house. In such cases a small discharge will
simply be held by the main waste pipe, draining slowly past the blockage, while
a large discharge will cause a backup.
Foul septic odors in storm drainage piping, catch basins, footing drain
piping or curtain drain discharges may indicate that sewage from your
property or an adjacent one is entering these ground water
systems.
Sources of Information about your particular septic system
What can a prospective purchaser of a home do to gather as much information as
possible relative to the present condition of a system and about
possible future expenses associated with the septic system? Here are a few
suggestions:
Obtain Information about the septic system from the present property owner
Ask for any drawings regarding the actual location (an "as-built drawing)
of the existing septic system.
Ask for the records regarding maintenance of the system; Has the septic
tank been pumped at a frequency of at least 3 to 5 years?; What pumping
contractor was used?; If the system contains a pump. how often has it been
maintained?; If major repairs have been made, when and to what extent?
Ask about the past performance of the system. Have any of the
symptoms described earlier manifested during the life of the
system?
Make a Visual Site Inspection of Septic System Condition at the Property
Once the locations of the septic tank and leaching fields are known, walk
over the entire area and observe whether there is any evidence of a sewage
overflow condition. Greener grass in the leaching area may not necessarily
indicate a system problem. If, however the area is completely saturated and
odorous you should be very concerned. It most likely indicates an active
failure.
Try to get a sense of how natural conditions are effecting the capacity of
the property to disperse water. Is the sewage disposal area located In a
depression which would have a tendency to collect run-off of rain water? Is the
lot flat? Is there a water course of wetland (swamp) near the leaching system?
Is the system virtually at the same elevation as nearby wetlands? Are
there steep slopes and/or ledge outcrops which reduce the available area for
leaching purposes? All of the above factors could indicate that the existing
system will experience difficulty or, that there may not be much additional
area suitable for sewage disposal on the lot if needed in the future.
Go to Town Health Department to Review the Property's Septic System Information File
Ask the town sanitarian to review the file with you. Is there enough
information in it for him/her to give you an opinion on how the existing system
and/or lot meets present health code requirements?
Ask for the records regarding maintenance of the system; Has the septic
tank been pumped at a frequency of at least 3 to 5 years? What pumping
contractor was used? If the system contains a pump, how often has it been
maintained?; If major repairs have been made, when and to what extent?
Your goal is to, confirm and supplement information received from the
property owner.
Obtain guidelines concerning the proper maintenance of a subsurface sewage
disposal system.
If you are contemplating an addition to the home or plan on renovating an
unfinished basement discuss the possibilities with the sanitarian and determine
the procedures you would have to follow to accomplish your plans. In wm cases
it will not be possible to "enlarge" an existing home.
Ask about the general neighborhood, the frequency of repairs, ability to
install proper size repair systems, average life of systems in the area,
etc.
Obtain Additional Information from Outside Sources
Presently many home sales are contingent upon a home Inspection. Part
of the inspection usually includes a test of the existing septic system.
[Note: Septic Tests are beyond the scope of a professional home inspection
but are offered as an additional for-fee service by most home inspectors who
serve areas where private systems are common.]
Unfortunately many of the
people performing these tests do not have a complete understanding of how a
systems function and may perform only a perfunctory test such as a low-water volume or using an insufficient
amount of tracer dye. Therefore, the conclusions reached from these tests are often
misleading. Be sure your test is performed by an expert.
Three common septic tests performed during home inspections are:
The Septic Loading and Dye Test (properly a "septic loading and dye test)
is used to trace the movement of septic tank effluent
into the leaching system. The theory is that if the dye "surfaces" to the
ground or appears in a brook or catch basin the system is in trouble.
Although
this is indeed true, the opposite result does not necessarily mean the system
is - functioning or will function properly In the future. In order for the dye
to appear it must flow through the septic tank and leaching fields prior to
arriving at the breakout point. This usually would take a large amount of water
and sufficient time to occur, and most home Inspections do not last long enough
to fulfill this requirement.
[DJF note: This opinion of the Health Department is not entirely
accurate. National data collected among professional home inspectors between
1985 and 1995 indicated that a significant number of inspectors performing dye
tests discovered total failure of the septic system within 20 to 30 minutes of
beginning testing.
We agree that a dye test is by no means a complete test of a
system, that the other measures suggested here are extremely valuable, and that
the volume of water used is critical: too little or too much can both be
serious mistakes. If a wet area or soggy area is present, dye has been found to
appear in the short time indicated.
However beware: NYS DEC has found dye
appearing in nearby streams as late as five days following a septic dye test in
cases where effluent migrates through considerable ground area before entering
a stream.
Probe Test is a procedure whereby the Inspector attempts to locate
the "key" elements of the system (septic tanks and leach fields) and determine
if they are experiencing hydraulic distress (meaning the septic tank and fields
are flooded). This test is basically inaccurate since it only takes a single
"snapshot the condition of the system. It may be a "good" day for the system
(very little water was used by the homeowner that day; the house may have been
empty for some time; it may be the middle of the summer when soil conditions
are at their best and a judgment is being made with very little long term
information.
[DJF notes: WARNING: probing can damage buried equipment such as fiberglass
septic tanks or tank covers or plastic septic drain lines. Further, there is little assurance that the probing is
done in the area where a problem is present.]
The flooding "test" is actually the process of discharging a vast
amount of water into the existing system. Depending on the number of fixtures
utilized, an additional 500 to 1,000 gallons of water can enter the ' system
during the course of an Inspection.
The inspector then examines the leaching area to observe any signs of an
"overflow condition." If none is noted, it is assumed the system is functioning
property. This type of test is most disturbing since it can actually do harm to
the system by "artificially" flooding the septic tank and fields. This could
lead to suspended solids escaping the tank, causing increased clogging to the
leaching fields.
Also, the results of such a test can be misleading in that the
prior use of the system (both over and under utilization) will have a direct
bearing on the outcome of the "test."
[DJF note: the opinion of CT DOH that an inspector injects 500 to 1,000
gallons of water contradicts the earlier DOH opinion that held that it is impossible to
inject significant volumes of water into a system during a typical 3 hour home
inspection. It is easy to place 200 to 500 gallons into a septic system
during a three to four hour home inspection. 1000 gallons would be a bit high.
Even if a high available water flow rate in a building makes it possible to place
very large volumes of water into a private septic system, we advise
against attempting flooding tests (very large volumes) as in cases where the type of septic system
is unknown it is possible to damage or even destroy the system leading to very
costly and previously unnecessary repairs.
A test which greatly exceeds the design
parameters of the system is a questionable procedure. The Septic Information
Website describes appropriate procedures for performing various septic
tests based on a national survey of inspection and engineering practices.]
Use of Soil Conservation Service County Soil Maps (through the town
sanitarian), try to identify the type of soil most likely present on the site
in order to predict the feasibility of future repairs to the existing leaching
system.
Talk to neighbors about the general performance of septic systems In the
area and specifically the system on the property you're Interested In. However,
this is suggested only for those comfortable approaching this subject with
strangers and with the realization that the information gathered may not be
totally factual for various reasons (devaluation of their own property; not
wanting to spoil the sale of a friendly neighbor, etc.)
Hire your own septic test consultant either a professional engineer [who is
specifically familiar with septic system design and repair], an inspector who
has experience with and is familiar with septic loading and dye testing standards,
a licensed septic inspector (in states which license this specialty such as MA), or a licensed
septic system installer, who performs a great deal of work in the particular
town. They can give you advise as to the condition of the soils and septic
systems In the area and what might be expected (especially pertaining to costs)
if/when you find problems with the existing system.
[DF addition: After performing the septic loading and dye test and obtaining
whatever historical maintenance and repair information you can obtain from the prior owner,
depending on the septic system condition and when it was last pumped, you may want a septic
contractor to located, open, pump, and inspect the septic tank. More details about this
step are at Performinga Septic Loading and Dye Test,Septic System Inspection Methods and Procedures,
and
Obtain water meter readings (if the home is serviced by a municipal water
supply) to determine what the present occupants of the home are utilizing. Then
compare those results with what your family is presently using. If your family
Is using significantly more water than the former occupants you may be asking for
trouble if the sewage system is undersized by today's
standards.
Additional useful information which may be available from the service
company who has pumped the tank recently includes the following:
Type of tank material - old steel tank may be at or end useful life
Tank size - along with usage determines appropriate pumping frequency and system capacity
Evidence of damage to tank components - broken baffles mean the leach fields are probably ruined
Evidence of backflow into the tank during start of pumping - indicates flooded leach field, probably failed
High sludge level and/or excessive floating scum level - indicate high risk of having pushed solids out into the leach field, destroying it
If the system has not been cleaned in several years and if the seller will
permit, have the tank pumped to obtain this additional information. Typical
pumpout fees are around $100. if excavation is not necessary. If the tank
location is unknown extra costs will be involved to locate and excavate it -
steps to which a seller is likely to object.
Home Buyers' Guide to Septic Systems - A Final Overview
It is our opinion that when buying a home, especially one that is old and does
not have a sewage disposal system that meets today's standards, the fundamental
questions that should be answered are:
Is the septic system currently working properly or is there evidence of a failure?
Even if it's working, are there signs suggesting short remaining life of the septic system?
When the existing system fails, how
will we repair it and how much will repairs cost?
If accurate soil test data is
not available through the local health department the only sure way of answering
the question is to actually perform all the deep hole testing and percolation
tests required by code.
As you can understand, most sellers would take a dim
view of prospective buyers wanting to tear up their property to perform then
tests. Therefore the more information a buyer can obtain, the better able he or
she will be able to judge the adequacy of the existing system and what will most
likely be required to repair the system, when needed. In that way, the buyer
will not be caught unaware when that day arrives, since it was part of the
financial assessment establishing the value of the property at the time of
purchase.
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This text was copied, edited, and supplemented by the website author from a
public document provided by the CT State DOH. Their contact information is: State of Connecticut Department of Health Services 150 Washington St., Hartford CT 06106 203-566-1292 Voice 203-566-2275 Fax
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