We have a reasonably-sized septic tank embedded in the front garden and
we understand that the previous owner had it cleaned every year, at a
cost of about £120. There has been a suggestion that this annual
cleaning is a bit excessive. On the other hand, I have read that if the
solids mount up and leave the tank and move into the soakaway area then
the soakaway area becomes clogged and you then have to build a new
septic tank at another (clean) spot - which is a real bother and a
considerable expense. So, clearly, regular cleaning is worthwhile.
But how often is regular for a two-person household?
Most people go about once a day ;)
You already have your answer. Once a year is a small price to protect
I bought a rural bungalow off a little old lady, who assured me the
drainage system was fine, but had the tank desludged twice a year.
Two weeks later it backed up (and that's as unpleasant as you
The pump out man said "Oh yes, the herringbone's wrecked - the old
lady had me round every 2 weeks".
First quote (this was 1999) was £6500 for a complete refit.
Eventually got that down to £2500 for retrofitting the tank as as
processor, environment agency approval, and certified clean outfall
into a river instead of a herringbone.
I am rather confused by this post. What is a "herringbone". My parents
had and old fashioned septic tank installed when the property was built
in 1939. During the war there was no opportunity to empty it, in fact
is was first emptied around 1950 and caused no problems. I had my
concrete septic tank replaced by a modern one on purchasing this
property in 1900, I have had the tank emptied once in that time.
Admittedly I am careful that no bleach or biological washing powders are
used, but it is fine, as I would expect. What does annoy me is that one
of my neighbour's cuts costs by having a local farmer empty theirs
instead of a property specialist, this saves then the fantastic sum of
£40. The farmer sprays his on his fields where as The specialist gives
you a certificate that his effluent is safely disposed in a sewage farm.
On Mon, 03 Dec 2007 17:33:04 +0000 Broadback wrote :
You need to distinguish between a cesspool, which is intended to store
waste until the truck comes to pump it away (though in the past a good few
had holes knocked in them to delay this necessity) and septic tanks which
are like mini sewage works with the treated effluent being discharged
The herringbone referred to is a branching pipe system which works in the
opposite way to land drains: instead of collecting ground water to a
central point, the effluent flows out from the central point (tank outlet)
through the perforated drains and out into the soil.
Tony Bryer SDA UK 'Software to build on' http://www.sda.co.uk
Try reporting it to the Environment Agency. They quite rightly take a very
serious view of it. It is good practice to have a properly functioning
septic tank emptied annually. It should certainly be examined annually to
ensure it IS functioning correctly.
Sounds like a good idea, getting the local farmer to suck it out and
spray it round, but surely that is illegal. They used to do this on a
grand scale in places like India and it accounted for quite a few
diseases, i.e. human poo on lettuces etc!!!!
My neighbours septic tank/cesspool frequently overflows (as it is mucky
stuff I assume it is a cesspool, as surely the whole point of septic
tanks is that they remove the nasties and just water overflows)into the
stream below, which then flows into the River Trent. A complaint by
another neighbour to the environment agency saw no response!
Septic "tanks" are actually a number of tanks in series. If they
overflow, it's usually the early tank(s) that do it first and they're
just as bad as a cesspool.
True cesspools rarely "overflow frequently" as they shouldn't be taking
groundwater and they can't otherwise fill fast enough to do it
"frequently". Running rainwater into a cesspool is a good way to do it
Depends on the size of the house. We are rated to have a 6 person tank,
but there's two of us and 4 cats..ask not why a lot of catshit goes down
it..and once every 4-6 years seems about right.
But ours is a modern biodisc. I never cleared the old septic tank ever
in 7 years. It whiffed anyway. It probably could have used a flush.
On Mon, 03 Dec 2007 15:44:33 GMT, Eddy Bentley
I suppose it depends on how big the tank is but ours is de-sludged
every two years, the recommended period, by our council (£120 a year
I imagine our tank is quite large as it hadn't been de-sludged in five
years at least and it was nowhere near full. Funnily enough, you would
think it would pong to high heaven but the only smells were after it
had been emptied and then only for a week or so after.
Some additional information is required re this 'soakaway' and the age
and structure of the tank.
If it is an old system in the style of two tanks and an outflow to a
local stream, then experience shows that pumping out annually, or ten
yearly even, isn't necessary. Actually ten years is possibly a bit of
a limit, but seriously for that sort of tank every 5 years is more
I can well understand, having had a blockage in my 60 year old outlet
to the stream, that a blockage in a herring bone system could be
fatal. In fact I'm not sure that regular pumping out would prevent
this as the demise of my outlet was ingress of soil particles etc.
into the field type drain to the burn.
I'll second that, just, last weekend, cleared a blockage of some years
standing in a 4" pipe. It was about 150' to 200' long with a drop of
about 5 feet and full of YUK, it had a loose join and had been flowing
above ground for quite some time unobserved. It is in an area that
doesn't often get visited. Anyway the effect of the head and the shaking
up that the jetter had done was rather spectacular!!! A large jet of
greyish fluid flying through the air, ugh.
The main blockage in this case seemed to be a sponge that had found its
way through a septic tank and into the outflow pipe, plus a few other
bits that should never have gone down the loo.
It seems to depend on how much you cherish the bacteria in the tank. Damage
them with household chemicals and they'll go on strike, nurture them and
they'll do all the work for you - and save money, worry and other costs.
The point of a septic tank is that it takes raw sewage with its large
lumps of organic matter, settles them out and that they then digest
and lose much of their solids content as gases - methane and CO2 if
it's working well, hydrogen sulphide if not. You then have only water
and undigestable solid matter to handle.
The water which is still full of soluble organic matter percolates
through the soil via a soakaway and bacteria treat it quite safely
providing your soakaway is properly sized and the soil is suitably
permeable. My recollection of the design standard for septic tank
sizing is that it assumes desludging at not more than once in 12
months. In practice it may go for a lot longer.
According to a vey useful book about septic tanks which I bought at
CAT last year, the bacteria are practically indestructible. Even if
you try to kill them off with lots of bleach - people have done this
experiment, it seems - they'll be back to fll strength within a matter
On Tue, 4 Dec 2007 08:57:48 -0800 (PST), The Real Doctor
You don't just need to "have bacteria in" a septic tank, you need to
have a population that's largely of the right sort, and you need to have
them working for you. If you affect the oxygen availability in there
then you might not kill them off, but you'll stop them working in favour
of the anerobes (the hydrogen sulphide makers).
We were somewhere around Barstow, on the edge of the desert, when the
drugs began to take hold. I remember Eddy Bentley
Every 5 or 6 years for that use. More often is a waste of time and money
and anyone who tells you different is talking out of their arse.
I'm no expert but a few points that I don't see raised that the contractors
who empty mine made:
Septic tanks are/should be sized to the house so there is the balance
between number of users/size of tank/frequency of emptying.
The "bottle" tanks with the floating ball can be knackered before the
soakaway gets damaged. The solids accumulate under the ball and it can
become impossible to depress the ball to get even a small suction pipe
into the tank.
The undigested solids settle at the bottom of the tank and if left too long
will not be sucked up and unless the operator goes out of his way to
properly empty the tank it starts to loose capacity and in effect becomes
too small for the house. (no matter how big the pump is it's sucking and
1bar is all you can get)
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