Anatomy of a sceptic tank

[johnM]

Yesterday I was faced with the enviable task of unblocking the drains between the house and the sceptic tank.

I had put 7 lengths of drain rod down the drain that the bathroom waste flows into and I couldn't get any further, not sure if I hit a corner or the blockage.

Then I tried lifting the cover on the sceptic tank, didn't smell too bad to be honest a bit like a mix between boiled eggs and soup, and could see the three openings as illustrated above.

I then fed two lengths of rod down the left-hand drain as the water level was higher than the main chamber, this was successful and with a bit of wiggling of rod and gurgling of tank all was cleared.

Would anyone know how the tank works with these two other drains, are they there for the purpose of clearing blockages?

[Jack]

Gidday

How a septic tank works is, the gunk comes in through the pipe from the house and into the chamber where there should be a "T" join, one going up to the air to stop the surge of air in the pipe blocking the incomine with an air lock and the other going down into the lower part of the chamber so that the incoming gets down below the crust. There the little helpers eat it all up and the dear little soles'dead bodies are what causes the scum. The outlet should be from below the scum also and that should go out to some sorta drainage or soakage either directly down or into a field so that it has a wider area to soak away into the soil.

Often the problems of blockage are caused by roots getting into the pipes or the soakage not working properly so holding the level of poos too high in the chamber to allow a free flow from the house.

The grey water from the bath, basins etc. can also overload the system.

[ina]

Oh dear - maybe you should ask Diana, she had a major septic tank problem not long ago... And if there are any Scottish peculiarities about septic tanks, she'd know that, too!

[Muddypause]

Jack's got it - one soil pipe is an inlet. t'other is the (liquid) outlet that should lead to some sort of outfall or soakaway. There are chambers inside the tank to separate soilids from liquid.

If properly installed, the soilpipes leading to it should have some sort of rodding access point (eg a manhole, or a smaller rodding chamber) where ever there is a bend in the pipe, so that it is rodable along its whole length.

Also, septic tanks do need emptying every so often - some people say as often as once a year.

[camillitech]

it's important not to use bleach or strong chemicals with a septic tank as it kills the bacteria that digest the crap. my original septic tank had not been emptied ever and it was in excess of 20 years old i only replaced it because the sides collapsed (a fault with this type) i fitted one of the new onion shaped ones a couple of years ago and started it off with a couple of dead rabbits



the old one is just behind the digger and is tiny by comparison, so if you don't go bonkers with the chemicals and your pipe work in and out is good they should never need emptying. if you have 6 children an automatic washing machine and a wife with a fondness for 'mr muscle' be prepared to call in the s**t tanker