Is the area that is still wet the same areas you had pooling? Was the shower pan flood tested? Proper slope? What kind of tiles? Do you have any in progress pictures?

The pooling was within those areas but only about softball size. The shower pan wasn’t flood tested. I know there was a minor slope on the sub floor before the pan liner was put in. The floors are ceramic and wall is porcelain. Tec Power Grout was used.

First, your grout and mortar beneath the tile are not waterproof. Even a single grain of sand is porous. It will get wet and soak up water underneath your tile, so the mortar needs a mechanism to drain. I attached a photo so you can see near the drain pipe in the photo center lower edge and reference to "pea gravel to cover weep holes". Small weep holes exist to allow the MORTAR to drain as it will get wet - through the grout and even through the tile. Even the tile, whether ceramic or porcelain is NOT a waterproof surface (unless a glass-like glazed surface). You can see in this image, the shower pan liner is the waterproofing membrane going up the wall on the left and over the curb on the right. It also seals to the drain base. But above that base is the female threaded collar which accepts the upper section of drain. That female threaded collar has weep holes which should be covered with pea gravel so that mortar does not get into them while spreading mortar for the tiles. Different drain systems and styles have different mechanisms that allow the mortar beneath the tile to drain.

Most of the shower water washes over the tile and grout and goes down the drain you see in the shower. But water also soaks through the grout and the mortar down to the waterproof membrane beneath that routes it to the drain assembly where the weep holes allow drainage. While excess water drains through weep holes, most will evaporate upward - the same way it entered the grout and mortar. The fact that you have a linear drain does not change this fact of shower drainage. Under your tiles exists a bed of mortar on top of some method of waterproofing. This bed of mortar MUST drain or it WILL fail. First the grout will discolor. Then the tiles will discolor. Then it will all come loose.

Generally, people take their showers during one particular time of day, then the shower is unused until the following day. The mortar and grout will dry out during the downtime - certainly within a 24 hour period. Perhaps what you see is simply a grout discoloration from first-time-wet and it has changed color from its original. I would not be worried about the couple of softball sized wet areas. In a custom shower, especially if a mud pan was made, it is not unusual to have a low area here and there. It is hard to be 100% perfect with setting tile. But if the grout IS actually wet - there may be a problem. It should dry in a 24 hour period.

From what I can see of the floor tile and wall tile - it looks like a fantastic job! No rookie did this. Bruce @ Elk Ridge Remodeling Co. 608.921.1074

I wonder if the grout is a little lower than where the lip of the drain is so that the last bit of water doesn't have enough momentum to get over it so it sits...

Just a thought...

Good luck!

@ Elk Ridge - Good explanation but you may want to consider deleting that diagram.

1) no wire mesh.

2) waterproof drywall????