Do I have a fosse?

[IanB]

I'm confused. I hope someone with great experience can tell me what to do.

I'm in the process of buying an old house in the middle of a village. The  ground (house and garden) isn't big (approx. 30M x 20M), with roads on three sides and an assortment of houses on the fourth. I assumed that, because of the location and the size of the garden, we were on mains drainage.

However, I've just received the Compromis de Vente for signature, and it says:

"..il n'existe pas de reseau public d'assainissement"

"  une installation d'assainissement privee exist depuis une date inconnue..."

etc

etc

How do I find out exactly what the position is? (To be honest, we'll buy the house whatever the answer is, but I need to know for planning/budgeting purposes before we arrive to take ownership.) I thought of calling Le Mairie, (he's based in the village) but that could be quite a challenging call given my spoken French.

Any ideas, help, words of guidance will be gratefully received.

[Matt]

We're in exactly the same position.We are having fosse inspections in our village and our compromis de vente says the same as yours.I couldn't find the "private system" anywhere so I emailed the selling agent.Its over 18 months since we bought but the very helpful lady at the agents has been in touch with the previous owner who is drawing us a plan of where it is.

[Nick Trollope]

That says you have a fosse (of a type non-specified from an unknown date) and that there is no public sewer available. The obvious answer is to get (or get the vendor to get) an inspection from a professional or SPANC (wonderful acronym). Your Notaire or agent will sort this, if you ask.

 

[IanB]

Nick, on your advice, I've gone back to the Notaire and asked for full information on the (alleged) fosse, including a report by SPANC. I also phoned the Maire's secretary, and (I think) he confirmed that the house didn't have "l'assainisement tout à l'égout".

I supppose it was too much to expect....

Thank you both for your help.

[IanB]

Well, the Notaire has responded by faxing me a report from SAUR. It seems that the seller has already applied for (and been granted) permission for a new fosse.  However, there are a couple of points I'd be grateful if someone could explain. (The workings of septic tanks are new to me - it's not how I planned to spend my retirement....).

A. It says I must have a Fosse toutes eaux "avec Filtre Decolloideur integre". I can't find any mention in past threads of such a filtre - is it unusual or does everybody have one?

B. The output from the fosse goes to a vertical zeolite filter bed (LFVD zeolite), with a dimension of 5 somethings - linear or square metres. I assume square?

C. The output goes into the "Reseau EP Communal", with the permission of Le Mairie, of course. However, according to the drawing supplied, it goes via a "caniveau" (gutter?) in the street beside my garden wall to a nearby "avaloir" (gully?). Does that sound right? Sounds perilously like an open sewer. Shouldn't I have to dig up and join into the public drainage system?

Any help will be gratefully received.

[BJSLIV]

All the dirty water etc produced within your house goes into the fosse. Hence its name Toutes Eaux. Once its in the fosse bacteria set about digesting the solids, which settle as a mud at the bottom of the tank. This has to be emptied from time to time, typically every two years.

The liquid drains away through the filter bed. If the filter bed were to get contaminated with floating solids it has to be replaced (Expensive!) so the Filtre Decolloiduer sits between the tank,  or in your case is part of the tank, and traps any solids before they reach the filter bed.

Rainwater goes direct from the roof to the Reseau Eau Pluvial (EP), which is usually a simple ditch. The output from your fosse being dispersed through the filter bed has nothing to do with the "Reseau" . As far as connecting to the public drainage system is concerned, if that existed you wouldn't be needing a fosse in the first place.....[:D] 

This gives an idea of how it works and fits together.

http://www.sebico.com/upload/doc/notici-de-pose-assnt.pdf

 

 

[IanB]

BJSLIV, many thanks for the info and the link. It's very informative.

I think I understand better now how my fosse will work, but I'm still a bit confused about the last stage of the process - probably, I'm misunderstanding what the paperwork says. If I can ask your advice once more?

1. The drawing is not very clear, but appears to show the (an?) output from the LFVD going out of my garden into the caniveau and thence the avaloir.

2. The form describes three stages of "processing"

       A. Pretraitement - the fosse and filtre

       B. Traitement - the LFVD

       C. Rejet - into Reseau EP communal (with authorisation from la mairie)

I assumed that No.1 and No.2.C were the same. Am I wrong?

(NB, the americans have a saying: "Never assume, it makes an ass out of you and me"....)

[Nick Trollope]

As I understand it, a zeolite filter is just that - a filter, it is not a soakaway. They are used where space is a premium. Once filtered, the water is passed (or more likely pumped) to a suitable place for disposal - such as a ditch or gutter.

 

[BJSLIV]

I wonder if its because of the terrain (poor drainage?) or lack of space etc etc, but they do seem to be suggesting a hybrid solution. Having cleaned up the waters as much as possible through the tank, instead of the liquids dispersing from a large drainage field, you have a smaller filter bed  and  the, by then, non-contaminated water just runs away down the ditch.

This is a document from the Lot SPANC which shows such a set up. It even refers to  an area of 5 sq metres.

http://www.lot.fr/spanc/fichetechniquefiltrecompact.pdf

 

[IanB]

BJSLIV, thank you for the link. The document is very useful (as was the other link you provided). I think such a solution has been proposed/agreed because of the lack of space - the house hasn't got enough space round it for a traditional filter bed. Which is also what you suggested, Nick, (but I think we can get away without pumping, as the ground slopes nicely).

The SPANC document worries me slightly though. It says "Ce dispositif ne peut etre utilise pour les habitations de 5 pieces principales au plus (3 chambres)". I translate that as meaning "only for houses with five main rooms at most (three beds)". That could be a serious limitation in the future, as the house will grow beyond that sometime.

Would making the fosse and the LFVD bigger buy me more rooms? If it's as simple as that, I can apply to SAUR for revised permission, and just install a bigger fosse and filter bed when we get the work done. Or, horrible thought, am I at the limit of this design?

Thanks for your patience with the continuing questions - I do appreciate your help.