Haestad SewerCAD is good, but expensive.  They used to be the only game in town, but I would guess there are cheaper now.

Engineering is the practice of the art of science - Steve

SewerCAD is extremely limited in what it claims to do; that is, interface between pressure and gravity. It cannot model an ARV, which makes it entirely useless as far as I'm concerned.

Don't get me wrong, it's workable for modeling a single lift station, but I had to use it to model a 1,000+ pipe network with 40+ lift stations and a variable control point on the main trunk line.  I ended up doing a lot of iteration by hand because it doesn't have a scripting module (SewerGEMS does, but also can't model an ARV) and can't cope with the high point on the pressure line being anywhere but the end.  

You have to do bolted manholes on gravity sewer beyond the control point and modify the end elevation of your last pressure pipe to match your HGL, which gets all kinds of fun when you have 12 lift stations manifolding downstream of your control point, which shifts depending on which stations are running, and you're modeling 24 hours.  

Instead of one model, I ended up with about six, where I could only run the simulation for a few hours before having to change all the elevations on all my pressure lines, input new lift station levels, run for a few more hours, etc.

In that event, Francesca, what model would you recommend?

SewerCAD is the only one I've used.  I believe other consultants used SWMM to model one of the city's other sewer basins.  I haven't used SWMM, though, so I can't comment on how well it handled that application.

An Env Engineer I work with also uses SWMM to model sewers, he seems satisfied with it.

Engineering is the practice of the art of science - Steve