In short, the main obligations of homeowner are to install an independent sanitation system and to ensure its regular maintenance. And don’t forget the obligation to include a sanitation diagnosis in the DDT (technical diagnosis file) if you wish to put up for sale a house that is not connected to the public sewerage system.

The NCS installations must not cause olfactory nuisances (*), nor favour the development of mosquito breeding grounds likely to transmit vector-borne diseases.
They must not present any risk of pollution of groundwater (**) or surface water. They must be installed at more than 35m from a declared well (for sand filters).

(*) For bad smells: In case of problems, if a complaint has been filed against the owner of an installation that emits bad smells by a neighbor for example, the installation can be considered as non-conforming (Order of April 27, 2012, Annex 2 "modalities of evaluation of the installations", paragraph 1.1 "problems observed on the installation").

(**) Concerning groundwater pollution: The current regulation imposes a distance of 1m between the bottom of the infiltration trenches and the roof of the water table (or perched water table) Article 6 point e) of the decree of September 7th 2009. This is to leave a safety distance between the arrival of the water from the all-water tank and the water table. This precaution allows for the partial filtration of this water to limit the pollution of groundwater. This precaution does not exist for sand filters. Their rejection partially treated in the layer of sand brought goes directly to the groundwater. This provision, which legally allows groundwater to be degraded, will probably change. In this case, the installations in place could be out of standards.

It concerns sanitation installations built after September 7th 2009. It insists on the fact of avoiding the clogging of the materials used, of having the file validated by the SPANC before doing the work, of sizing the installation according to the number of main rooms, and of studying the capacity of the soil to treat and infiltrate.

To implement a soil treatment facility, the following conditions must be met:

• Item a: The plot area is sufficient to allow for the installation of a soil-based treatment facility.
• Item b: The parcel is not recognized as being in a flood zone, except in exceptional circumstances.
• Point c: The slope of the land allows an installation in good conditions.
• Point d: The soil must be sufficiently infiltrating (permeability between 15mm and 500mm per hour) over a minimum thickness of 70 cm between the water line of the water inlet pipe of the all-water tank and the bottom of the trench.
  The control of conception and realization on the new or rehabilitated works.
• Point e: Concerning the protection of groundwater, check the distance of 1m minimum between the roof of the aquifer (or perched groundwater) and the bottom of the excavation.

If these 5 conditions are not met, the treatment by the ground is not legally possible. The user will therefore have the choice between the different approved microstations.

Treated wastewater (i.e. from a drained sand filter or a micro plant) cannot be discharged into a cesspool or a lost well (*). Only the technique of infiltration well in an underlying layer with a permeability between 10 and 500 mm per hour can be used under certain conditions (hydrogeological study in particular).

(*): Prohibited technique in order to avoid sending directly into the water table (perched or groundwater) discharges that always contain more or less toxic bacteria that could remain in the water table and contaminate it durably.

Emptying must be done only by an emptying company approved by the prefecture.

The owner of the NCS installation must ensure its maintenance, its proper functioning and its emptying. He must ensure the proper distribution of wastewater in the treatment or infiltration areas (*). The manholes (also called connection boxes) must be closed and permanently accessible for controls.
 
(*): For a good distribution of the effluents in time, a trough flush is strongly recommended to ensure the distribution of the effluents in the different branches of the infiltration zone. In fact, over time, the distribution holes can "move", particularly due to the irregular settlement of the soil. The arrival of low flow in an unbalanced manhole will send all the water to the same branch and accelerate its clogging. The bucket flush avoids this inconvenience.

A Unified Technical Document is a normative text written by the profession. It constitutes a common reference for all the participants of the building industry: project owners, project managers, companies, craftsmen, technical controllers, insurance experts...
Not respecting the DTU can lead to the exclusion of guarantees offered by individual insurance policies. For the end customer, it is the certainty of the realization by professionals of works in conformity with the rules of art (choice of products and implementation).
 
A DTU has two functions:

• To present the traditional works, their fields of use and the associated products.
• To describe the stages of implementation.

For houses up to 20 PE (Population Equivalent) or 20 PP (Main rooms), only one DTU: NF DTU 64.1
 
In addition to the legal texts, three aspects related to the installation of an individual purification system seem to us very important:

•   Insurances and guarantees: the good practices to be protected from a hidden defect or in case of disaster.
• To subscribe an insurance "Damages works".

According to the article L.242-1 of the insurance code, before carrying out any construction work, the owners can subscribe to an insurance which allows the owner to be reimbursed or to have the work done before the court decision on the responsibilities of each one is pronounced.
Check that the installer has a ten-year insurance policy
And remind the installer (if necessary) that the ministerial approvals issued must include a "user guide". This user's guide specifies the installation conditions of the approved devices. These are the installation conditions recommended by the manufacturer.

Site acceptance
Carry out a contradictory acceptance of the site according to articles 1792 and following of the civil code.
The reception of the building site is an important act of the building site. This operation is however very often neglected or not carried out at all. For the owner of the house, by the reception of building site, the owner accepts the building site with or without reserve. It is carried out contradictorily by the 2 parts (the owner and the company of installation). Following the acceptance of the work, the owner of the house becomes the owner of the work that has just been executed. If the acceptance of work is not carried out, a legal uncertainty exists on the fact of knowing who is legally the owner of the installation. The positions of the courts vary on this point.

In case of damage, what happens?
What are the consequences in terms of insurance if a micro STP (or any other tank) moves in the ground because of inadequate straps?
The responsibility for the damage is systematically attributed to the company that installed the device. Moreover, it will not be covered by its ten-year insurance policy since the risk that the straps would not resist during the ten-year insurance policy was quite foreseeable.
The engineering office that carried out the soil study file and SPANC would be totally relieved of a failure that does not correspond to their functions.

What if the damage is due to the straps not holding together properly after the ten-year period?
The owner of the structure will no longer be able to claim against the company that installed the device. The costs will be at his charge.

1. Prepare a complete file for the SPANC
   
   • The necessary information on the location of the house,
   • The surface and the nature of the soil available for sanitation,
   • The possibilities to infiltrate the discharge (or a study which justifies that no other solution is possible),
   • The agreement of the ditch owner (often the municipality) in case of discharge to the ditch,
   • The number of main rooms (which defines the number of equivalent inhabitants),
   • The type of possible solutions (sand filter, microstations, ...). Among these solutions, the private individual chooses the one that suits him best.
2. Present the file to the SPANC for analysis.
   This file is often prepared by a specialized design office. If the file is in conformity, the client can do the work. If not, the necessary corrections must be made.
3. In case of agreement, do not start the work without informing the SPANC
   Indeed, on the day of the work, the SPANC must be present to validate in particular the slopes of the pipes at the entrance and exit of the installations, the conditions for maintaining the station in wet soil (if you opt for a micro-station), the conditions of its backfilling, the type of discharge.
   The SPANC must also check that the installation complies with the file submitted by the individual and validated by him.

The French and flood-prone areas
While one French person out of four is located in a flood-prone area*, and one third of the jobs are exposed to flood risks*, the notion of flood-prone areas is still not well known.

A subject little discussed in the NCS world
The lack of clear and appropriate regulations is probably the reason for this.

According to article 6 of the decree of September 7, 2009, among the conditions that allow the installation of a wastewater treatment by soil in a floodable area: "The parcel is not in a floodable area, except in an exceptional way".

Through this file, we wish to bring you some precisions and a lighting on the concept of "Floodable Zone", its specificities and its consequences.

(Source: National Strategy for Flood Risk Management - Ministry of Ecology, Sustainable Development and Energy - Preliminary National Flood Risk Assessment - 2012)