Where is this leak coming from?

The fluid seems to be clear. Pictures are from the passengers side.

 

Just taste it.
Probably from your A/C condensate.

 

a/c, my guess

 

Since its August and you live in Arizona its safe to say that its condensation from running your air conditioning. If you touch/smell it you will find its just water.

 

That's what I thought. I'll put a cup under it next time and drink it.

 

I am almost 100% sure that be condensate fro your AC.

When it's humid out, I get a 3 ft. square puddle under mine.

 

Thats the only way to be sure.

 

The AC condenser exits right above the frame rail. Some guys mod it with a simple extension so it drains under the car and prevents future rust.

 

My knee jerk reaction is A/C condenser. As I understand Toyota stupidly put the condenser drain right over the frame.

 

Yep A/C. looks like H20