Using two chillers?

I made a wort chiller a few years ago and it works well but takes quite a while to cool down my 5 gallon batches and I hate the idea of wasting all of that water.

I had the idea of making another one to attach to the same "line" as the other. The water would go from my outdoor hose spigot to wort chiller #1 which is sitting in an ice bath, then flow to wort chiller #2 which would be in my hot wort. Do you all think this would be worth the cost and effort? Would this system cool down the wort much quicker?

this is a common practice. It's called a "pre-chiller".

Yes, it will help to chill faster - particularly if your ground water is pretty warm. In NC, you will likely see a big reduction in cooling time. Get a nice pre-chiller set up in a five gallon bucket, and you can fill it with ice water during the boil and have it ready to go when you hook up the main chiller.

What a novel idea...

Is this better than pumping ice cold water through your wort chiller? I use a small fountian pump in a cooler filled with ice and water after running tap water through for the first 5 minutes. I chill 5 gallons in about 20-25 minutes. My tap water is 80° too.

Pumping ice water through your chiller is more effective than using a pre-chiller, in my experience. I run tap water through my chiller to knock the temperature down to about 100º F, then switch to pumping ice water. I have a submersible 1/6 hp pump I got from Harbor Freight for about $50. I put this into a 20 gallon plastic tub with about 10-12 gallons of ice water and recirculate the water through my chiller to get down to pitching temperature. While I waste a few gallons cooling with tap water, it doesn't take very long to get to about 100º and the few gallons I use to recirculate is quite a bit less than what I would use trying to get from 100º to pitching temp. with tap water, or even with pre-chilled tap water.