Subject: Is there a mathematical relationship between the pH and conductivity of a liquid?

I have a project for a science fair and it is about sewer monitoring. I thought I could do that with pH, but  
I am going to send this [monitoring] data to the PC and use the conductivity of the substance to find the pH. 

Please, I need that relationship [between conductivity and pH] if you can give it to me. It doesn't matter 
if the relationship is complex; send it to me; I will understand or ask for help from a teacher.

Original Question:
¿hay una relacion matematica entre el pH y la conductividad de un liquido?

Tengo un proyecto para una feria tecnica y se trata de monitoreo de alcantarillas, 
pense hacerlo con pH pero este dato lo voy a mandar a la PC y con la conductividad 
de la sustancia encontrar el pH. Por favor necesito esa relacion si me la podrian 
ofrecer. No importa si la relacion es compleja envienmela yo la comprendere o 
pedire ayuda a un profesor

Re: Is there a mathematical relationship between the pH and conductivity of a liquid?