HomeMy WebLinkAbout1988-08-18 Letter, Septic System Inspection Follow UpCITY of ORONO
Post 0frecr Box 66• Crystal Bay. Minnesota 56= 0 Municipal O[tic•s
On the North Shore of Lake Minnetonka
August 18, 1988
Larry McGrath
3060 Parview Lane
Long Lake, MN 55356
Re: Septic System
Dear Mr. McGrath:
Marcella Lewin of Merrill Lynch Realty requested that I
inspect your septic system for purposes of satisfying a buyers'
mortgage. She indicated to me that someone from Inspect& Homes
had noted that the septic tank was "leaking".
I inspected your system on August 18, 1988 and would slake
the following comments in relation to that system:
1. There is no evidence of current or past seepage of
sewage to the surface from the drainfield area. There is
high grass over the drainfield trenches, indicating that the
system is probably being used to capacity and all portions
of the system appear to be in use.
2. An inspection of the first septic tank indicated that
the water level in that tank is above the normal outlet
level, hence there would appear to be some abnormal
restriction somewhere past that tank. The same high water
level was apparent in the second tank. The inspection pipe
in the first tank showed evidence of past sewage levels in
that tank as high as 12-180 above the normal flow line of
the tank, indicating that there has been a backup in those
tanks sometime in the recent past.
3. City records indicate that no pump out slips have ever
been submitted to the City, hence we can only assume it has
been a relatively long time since the tanks were pumped out.
The inspection pipes in the tank appear to be locat-d at the
ends and may be inside the baff les, hence it is impossible
to tell for sure whether those tanks are in need of pumping
at this time. However, the fact that the water level in the
tanks is abnormally high is an indication that there is some
problem with the system.
Since you are selling the house, to protect both you and the
buyer, I am suggesting the following course
of action to
determine the cause for this apparent p
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ASSESSING
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A) Uncover both tanks entirely and remove cover sections.
Have the tanks pumped out by a licensed septic tank pumper.
Have the pumper verify the proper elevations of inlet and
outlet pipes, verify the integrity of those pipes, and
repair or replace baffles within the tank as may be
necessary.
B) Uncover the first distribution box (and maybe additional
distribution boxes) in order to determine whether the flow
line is downhill from the tanks, and whether the drainfield
is saturated.
Your septic system was designed for a three to four bedroom
home based on soil testing done in 1977, which pre -dated the
current on -site system Code requirements. A review of the
original soil testing reveals that no indication of the existence
or non-existence of a seasonal water table was noted, which was
required after 1978. Such a seasonal water table was noted in
the property immediately to your west, and may exist on your
property. A seasonal water table near the surface has a
detrimental effect on trench -type drainfields, often limiting
their capacity. Because of that potential, it is not possible to
predict the actual capacity of your drainfield system nor is it
possible to predict with any degree of confidence whether that
system will continue to function for two weeks or another 20
years. This is typical of all systems which were constructed
prior to 1978 without accountability for seasonal water tables.
Given the above information, if it is determined that the
abnor-mally high water level in the tanks is due to a restriction
Paz': 'he tanks that can be cleared, and not due to some other_
f la- in the system, we would presume that the system wo,.,,1,3
continue to function adequately as it apparently has in the past.
Please feel free to contact me or City Inspector Lyle Oman
if you have any further questions. Please call for an inspection
when the tanks are opened for pumpout.
Sincerely %
Michael P. Gaff ,
Asst Planning & Zoning Administrator
MPG/tln
cc: Marcelia Lewin, Merrill Lynch Realty
Lyle Oman, Pield Inspector