The action of The National Sanitation Utility (ONAS) has extended beyond urban zones; indeed, ONAS was entrusted with a strategic study for the sanitation of rural zones, where wastewater has become a source of pollution as a result of an improvement in the rate of drinking water supply to these zones .

The study led to identifying 600 such zones which are in need of sanitation; these are zones where:
2 % of the are connected to the sewerage network;
23 % of the dispose of the wastewater in septic tanks;
75 % of the population dispose of wastewater in the wild.

The rural sanitation programme was initiated in 2001 by implementing a project currently involving 50 rural zones, distributed over the various regions of the country with a population of about 209 thousand inhabitants, followed upon by an evaluation of the technical, institutional and financial aspects during 2007.

The programme was designed to cover various regions of the country, and to encompass the experimentation of all possible sanitation (sewerage) modes, as well as to select appropriate and technically and economically proven cost-effective wastewater treatment plants, be they small-sized or integrated. Besides, emphasis was laid on maximising the use of treated wastewater as an alternative resource to meet certain developmental needs in the rural zones concerned.

The sanitation actions have so far been completed in 8 rural zones: these are Cherfech (Governorate of Ariana), Chouigui (Governorate of Manouba), Khanguet El Hojjaj, Oued El Khetaff , Beni Ayeche,Ain Kmicha ,Sidi jedidi (Governorate of Nabeul)  and Bechimet El Galb (Governorate of Gabès).

As regards  the second bid packageof the programme involving  the sanitation of 15 rural zones, the year 2009 reported :

1- the completion of  the sanitation works in 11 zones( Chouigui ,Nakta,Nianou & Fondek Jedid-Seltene,Tenbib, Hammam Bourguiba, Borgine,Knaeis, Khetmine, Zaouaouine and Saheb Jebal ),

2-  pursuing the sanitation works in the zones of , Souguia, Erriadh,Saida,,Ghezalla,. The completion of  the sanitation works in these zones is scheduled by the end of 2010.

 As regars the remaining 27 rural areas, a priority bid package is setteled comprising 12  rural areas finaced by The French Development Agency (AFD).The executive studies are currently underway and sanitation works programme due to be implemented in the period 2010-2014

It should be pointed out that the sanitation systems in rural environment are adapted according to the type of housing structure, and they often consist of individual or collective facilities which take into consideration the hydro-geological features of the substratum and the recipient medium. The systems are integrated, thus including the collection of the wastewater and its treatment, prior to its disposal in the natural environment.