Cess Pit Extension

[candiceH]

Hi... we've recently moved into a house which has a cess pit - something we're very unfamiliar with. The cess pit appears to fill very quickly. I understand that sewerage goes into the first pit in which the solids sit, then the overspill liquid pours into the second pit. My question is - can we dig a soakaway for the second pit to drain into? If so, what is the best way of doing this? Many thanks for any help and advice....

[mrpeter]

What you seem to be describing is a septic tank,i.e. two separate chambers. The second of these chambers the one with with only liquid in usually has an outlet through land drains of some sort.
If you have a cess pit this is usually one chamber that has no outlet and has to emptied by a licensed tanker service at regular intervals.
I do not think that you could create an outlet for a cess pit as this would pose contamination problems to other water courses in the area.

[buildersmate]

This is indeed a septic tank that you are describing.
See here for how it works (or how it is supposed to work).
http://en.wikipedia.org/wiki/Septic_tank
Clearly yours isn't percolating properly if the second tank is remaining filled with liquid - the design runs into a leach field where the excess liquid runs into the ground.
You are going to have some professional advice in. It may be cheaper in the long run to dig out the system and replace it with a modern Klargester type system.

[buildersmate]

Yes, just to clarify, if the system is working as it was designed, one has to have the solids in the first tank pumped out very infrequently (i.e. years between pumpings), but the liquids never need pumping out. They percolate safely into the ground.

[candiceH]

Thank you all so much for your help and advice. Of course you're all absolutely right.... It is a septic tank and it obviously isn't operating as it should be. It's an extremely old system. We had both tanks emptied just three weeks ago and the second tank is already nearly full. I wondered if the heavy rains have exacerbated the problem.... It seems we're going to have to (as you say) start again.... eeek ho hum. Thank you, again, for all your help! (Anyone good with a spade?!)

[buildersmate]

These type of installations come under Building Regulations Part H (Drainage) so one cannot just go digging holes in the ground.
It is very likely that recent extra rainwater is contributing to the problem because it raises the level of the groundwater in the immediate vicinity of your house. However for this to happen in summer is exceptional and it is likely that your percolating system is inadequate (in design). You really need professional advice on your options. Unlikely to be cheap, I'm afraid (several thousand).
On another angle, what level of survey did you have done when deciding to buy? A Homebuyers Survey should have investigated this and you may have some recourse.

[candiceH]

Thank you buildersmate.... am feeling rather weak at this moment in time! But have booked a drainage contractor to come and look at it in the morning. The diagnosis over the phone was exactly as you said. I bet my house insurance won't cover it either! Looked at my survey and it states that that private drainage does not cover the scope of their inspection. Oh well... you know how it goes.... thank you SO much for all your help - it's exactly what I needed....

[buildersmate]

The design principles behind septic tanks is pretty old but pretty reliable too - there's no reason to muck about with systems that is working OK. A key thing is the design of the leaching field, which may stretch over a quite a large area of land (say 40 square metres) - it's a fishbone-shaped set of drainage pipes and the higher the water-table, the bigger the system required to remove the liquid.
A day or two with a digger will re-create a new fishbone shape, then there's drainage pipes to lay, but I hope this isn't under your prize lawn.