Installing the Overflow from a Cistern

Though I certainly knew that overflow piping from cisterns existed, it had never hit home that I was going to have to put it in. Let's face it, all sorts of plumbing things intimidated me before...now. A couple months ago, my friend was putting in an overflow for his cistern and told me I needed to absolutely do it. I accepted it, mentally putting it on the list of stuff I would do before winter but didn't want to have to do any sooner than necessary.
It's really quite simple, and I'm sorry I won't have any pics of it till December or so, but will update this posting then. I went to ACE, which is my plumbing haven these days, and spent $40 on the outlet piece. I did 3" piping. Your outlet piping should be sized larger than your incoming (mine's 4") but 4" is a lot more expensive than 3" and I think that it should work fine. I have my cistern inlet above ground, and it's not a 100% sealed entry, so if it absolutely had to overflow there it could. In a normal setup, I believe people would have issues with backflow up their gutters.
You buy the piece, cut out a hole of that size (I used my friend's jigsaw) push it in, put the washers on the inside (I did at least), and hand tighten the outside piece, placing silicone between it and the tank. Then you put a threaded pvc piece into the outlet (I teflon taped mine) and then all the pvc piping and elbow that you need to take it as far away as you need to at a slight slope.

Voila! That's it. And you won't have a lake around your house when you come home.