Sewage System Question

lkkev80

Bought a new house last year, it is a 10 year old house in the country not on mains sewage system. Have been listening to all the talk in the media about the septic tank inspections and was looking at the system in the house - there is a gravel soak pit but I cannot see any septic tank - can this be the case?

Poor Uncle Tom

Short answer, No it cannot be the case.

If, as you say, the house is just 10 years old it has to have full planning permission including a site layout plan which should correspond to how your site is laid out. This will show where your sewerage is going and how it is to be treated. You can also check with your solicitor who helped in the purchase of the house, they should have adequate paperwork to point you in the right direction.

lkkev80

Thanks for the reply P.U.T. Was looking around the lawn, there is a manhole cover and under there is Y junction with 2 pipes from the house joining into one, then about 7/8m further on there is gravel which I presume is the soak pit - I don't see any manhole covers in between which is why I say I can't see a septic tank, I presume there is always a manhole cover at the top of the tank? unless it is covered by gravel? Will look for the planning details...

sydthebeat

lkkev80 wrote: »

Thanks for the reply P.U.T. Was looking around the lawn, there is a manhole cover and under there is Y junction with 2 pipes from the house joining into one, then about 7/8m further on there is gravel which I presume is the soak pit - I don't see any manhole covers in between which is why I say I can't see a septic tank, I presume there is always a manhole cover at the top of the tank? unless it is covered by gravel? Will look for the planning details...

the septic tank should be between the point at which a pipe comes into that Y junction manhole (this is a 'distribution box') and the SVP from the house, or from where the house foul system collects before being piped to the garden.

by right there shouldnt be a soak pit, there should be percolation pipes that may be laid on gravel trenches.... is there any sign of a pipe here? usually yellow flexible type....
there should also be vent pipes which exit the ground at the end of the percolation pies.
the septic tank should have an inspection manhole.

if its a case where theres *gulp* no septic tank, then thats a situation you need to remedy asap

rayjdav

sydthebeat wrote: »

the septic tankshould be between the point at which a pipe comes into that Y junction manhole (this is a 'distribution box') and the SVP from the house, or from where the house foul system collects before being piped to the garden.

by right there shouldnt be a soak pit, there should be percolation pipes that may be laid on gravel trenches.... is there any sign of a pipe here? usually yellow flexible type....
there should also be vent pipes which exit the ground at the end of the percolation pies.
the septic tank should have an inspection manhole.

if its a case where theres *gulp* no septic tank, then thats a situation you need to remedy asap

Just to clarify here,
The percolation pipes shoud NOT be yellow flexi pipe. They must be smooth walled perforated pipes.
Also, Syd is right that they should be laid on gravel, but preferrably you should not be able to see them from ground level. They must be covered by back fill of sort and geotextile membrane, to prevent ingress of soils etc blocking the perforations and trenches.
The manhole you see, this may be located 1m approx from your actual tank, on house side. Can you rod it to see? You may have foul services coming from different ends of the house (eg wc one end and say kitchen other end, and this is where they combine before the enter the tank inlet?). Unlikely to be a distribution box if the other items above are not installed correctly;)
You should have vertical 4" pipes local to all this to vent the system as noted above?

If not, I'd follow up on all this, especially as you only bought the place and it's only 10years old:eek::eek:

sydthebeat

hi rayjdav

i hadnt heard that the yellow flexis were not to be used... they are par for the course around here.

EPA states

"100-110mm bore,
perforated (typically at 4, 6 and 8 o’clock) smooth wall
PVC drainage pipes with perforations of 8 mm diameter at
about 75 mm centres along the pipe;

or

Pipes with similar hydraulic properties."

could it be argued that these flexi pipes have "similar hydraulic properties"??
Its my understanding that these pipes have been produced and designed specifically for percolation.

rayjdav

Syd,
Maybe so but as I read your post I understood it to be the standard flexi land drainage pipes. I personally have never seen anything bar perforated solid smooth wall 110mm pipes in percolation trenches as the flexi joints in the other type pipe could lead to clogging of the perforations from any part solid matter that may accedentially breach the outlet/distribution points of the tank/box.
I would have thought the the hydraulic properties refer to the resistance by the pipe of the acting forces, on completion of backfill of the trench, and that any other pipe must be able withstand the same values as that of standard 110mm PVC piping????

steelpete

septic tank would be on down hill side of house and could be a bit away, ours is about 100m away from house.

sydthebeat

rayjdav wrote: »

Syd,
Maybe so but as I read your post I understood it to be the standard flexi land drainage pipes. I personally have never seen anything bar perforated solid smooth wall 110mm pipes in percolation trenches as the flexi joints in the other type pipe could lead to clogging of the perforations from any part solid matter that may accedentially breach the outlet/distribution points of the tank/box.
I would have thought the the hydraulic properties refer to the resistance by the pipe of the acting forces, on completion of backfill of the trench, and that any other pipe must be able withstand the same values as that of standard 110mm PVC piping????

a very well known large pipe manufacturer has these flexi perforated pipes advertised for use in domestic septic tank applications. ??

muffler

I have seen all types of pipes used in perc. areas. The most common is the land drainage stuff which of course is not acceptable as its going to allow more water in than treated sewage out.

The pipes need to perforated on one side only with that side turned down on top of the gravel.

If you had the time you could make your own from solid piping, a drill and a 8mm bit

lkkev80

Thanks for replies. The Y junction box is very professionally done so as someone said I would hope the rest of the system is like that. There is a vent pipe up the side of house but no more vertical pipes - I thought there needs to be a vent pipe out of the septic tank? Is that right?
It's late and dark before I get home from work so it's hard to see anything - I will go digging at the weekend to see what I can find.