Can you take a picture and post it here? I have that in my current bathroom tile and it is bothersome...

Yes, pics! I've read a bunch about that here somewhere, maybe on Baths or Flooring? There's some technical guidance document somewhere for allowed lippage based on type of tile, etc, etc shall not be more than x plus the lesser of this or that so long as such and such conditions, etc, etc. A bit much for me to wade through, but if someone knows where that is it may help you figure out if it's in spec or just sloppy.

My backsplash has it. I didn't realize it was called "lippage." It's definitely because of the tile itself; its handmade look has corners that curve ever so slightly. It isn't noticeable at all unless my under-cabinet lights are on. So guess who doesn't like to use the UC lights anymore? :( After it was all over and done with, my tilesetter offered to reset various tiles, but convinced me that it was inherent in the tile itself and basically unavoidable. I'm living with it, but next time I do a backsplash or a shower or bathroom floor, I will look for a tile that is uniformly flat.

Lippage can occur from three different causes.

Reason number one is that the substrate isn't flat enough. This is by far the most common reason and the least addressed by either the contractor or homeowner. You can run into this a lot of backsplashes because the drywall wasn't done with tile in mind, and you get some "waves" where the seams butt. And it's the rare slab of concrete that is truly flat. The cure for that is better prep before install. A 4' level should be used to assess the flatness of the substrate, and then if there are any issues, that can be addressed before the tile goes up. That may mean grinding down a high spot in a slab, or it might mean addressing a deficiency in the joists that causes a hump, etc. (The wider the grout line, the more forgiving any installation is of an unlevel substrate. This can be especially important when people want natural stone, or very small grout lines. And that's just one of the reasons that such an install is much higher priced. Or should be if an actual tile pro is doing the work instead of just a "tile guy".)

Number two is the tile itself isn't quite flat. This happens most often with handmade tile, but it also happens with very large format tile. It just tends to bow from gravity affecting it during construction. Yes, even rectified porcelain can have this problem when you start getting 36" long tiles. That's why TCNA recommends a 1/3 running bond pattern rather than a 1/2 one, or else a stacked installation.

Number three is a sloppy installation by someone who just doesn't have the capability to do the job correctly. That's the #1 suspect in most homeowner's mind, but it's usually the least common cause if you've hired a true tile professional. Unfortunately, whether you're hiring a hack or a pro can be difficult to know up front. There really isn't a lot of oversight on tile contractors out there. Your best bet to get a good installer is to read up on what needs to be done yourself so that you can ask the right questions that will let you assess the knowledge base of the contractor. (Read up on tileusa.com or the John Bridge Tile Forum) A true tile professional will charge what he's worth though, even though you may think that high. In the case of Beagles, they made all the right noises and charged more than enough, but were still hacks, so also write a mutual dissolution clause into the contract so you can fire them if you aren't happy with the work they've done. (You can't just fire a contractor that you have a contract with, there are certain procedures to follow or you can have a lien put on your house.)

I tried the credit card test and most of the lippage is within industry standard.

I DO HAVE the BEST contractor. He called the tile guy back out and had him make repairs. There are two tiles that bother me... but... I went to take pictures to post here and it looks like those areas have been fixed!!!

My floor had ups and downs everywhere I looked before the install. It was a hard job and I know it. I'm 98% happy with the floor.