Hello Brian! Recently, I ...

Hello Brian!

Recently, I did an interesting course about Planning and Design of Sanitation Systems and Technology by the hand of Eawag and the École Polytechnique Fédérale de Lausanne. I can tell you that I learnt a lot thanks to this MOOC.

There isn't any "formula" to calculate the toilets; just you have to consider the domains (household, community and muninipal) and use the clues which are provided in guidelines like a Planning Framework for improving City or Rural-wide sanitation services. Take some case studies similar to your sanitation project; you'll always find the case studies really interesting. 

Sorry for going on and on :) I am going to get to the point:

You should design 1 toilet per household (always 1 toilet for 60 m^2).For public toilets in rural comunities you can project 1 toilet for every 25 people (I could study the case study in Lusaka (Zambia) and in this rural community there is a toilet for every 27 people).

To get affordable solutions, you have to keep in mind the type of sanitation system and the financial data; you should identificate the service options to do the action plan for:
- off-site (sewered) sanitation
- on-site sanitation (VIP latrines).

And finally, don't forget that in a sanitation planning you have to consider:

* the socio-cultural acceptance

*the government support

*the legal and regulatory framework

* the financial and institutional arrangements

* and your skills as engineer ;)