Water testing your Hot Mopped Shower Pan

Hot Mopping


All shower pans are required to be water tested per local building codes and for all warranty purposes for a minimum of 24 hrs. This serves a number of sound construction practices. It will show that the application of the hot mop is leak free at time of completion, when drained pre-pitch will be verified that water does indeed flow toward the drain, and it will especially show that the weep holes are clear and functioning properly, and also that the drain to waste pipe connection is leak free. Knowing that your hot mopped shower pan has been properly tested and its integrity is 100% is as important to us at Dk showerPans as it is to you.

Heavy or careless construction traffic, construction changes, job site mishaps, can and do cause damage and/or can cause your hot mopped showerpan to be compromised. If any visible damage is seen or suspected, a secondary water-test should be done prior to the tile contractors starting. Damage to a fairly new hot mopped shower pan can be repaired usually with-out tearing out the entire hot mop.


Making sure your pan holds water is the last step you need to do before you can continue building your new shower. A plug that is set below the weep holes is needed, a common mistake is that the drain top is covered with tape and when the pan is filled the water will still exit via the weep holes, as it should!!!

To get the plug below the weep holes, you will need to remove the drain screen by removing the two Philip screws that are securing it to the drain, do not loosen the bolts that hold the top flange to the bottom flange! If that happens you will need to have your drain area re-mopped to get the drain assembly to be water tight!

With adjustable drains you only have to un-screw the screen flange from the upper flange,do not loosen the bolts holding down the top flange to the bottom flange!!! Insert your 2″ drain plug,(on some adjustable drains only certain types of mechanical test plugs can be used!) if you tighten the wing nut so the rubber stopper on the plug expands slightly before you insert into the bottom of your drain fits it is easier to do the final tightening. Make sure you seat the drain plug and finish tightening the plug, the use of a pair of needle nose pliers makes this part real easy. Fill your hot mopped shower pan with water to with in 1″ of the top of the curb.

Let sit for 24 hours and then check around all walls and/or ceiling areas. If the water level has dropped and you do not see any visible signs of water your plug may not have held… it has happened more than a few times, at this point remove plug and throughly clean the area inside the pipe, ABS glue of burrs of the plastic may have not let the rubber plug seal completely, in some cases a inflatable bladder plug may have to be used if you can’t get a mechanical plug to hold, just be careful not to over inflate it could damage your drain connection!

Now remove the plug and let the water drain, as it gets lower than the drain collar you can look inside the drain and should be able to see water coming though the weep holes, usually 3 of them, if more flow is coming out of one than another take a nail or punch and ream the holes out!!! This always a good practice to do, the weep holes serve a important part in your shower pan and need to be keep clear, weep hole protectors, broken pieces of tile, or small pebbles placed around the drain body are a common practice as to not let the dry-pack application clog or slow down the weep hole function.

As the water drains it should travel from all areas to the weeps no puddles should remain in your pan. Attach drain screen and you now know that your hot mop shower pan is ready for your finished materials!!!

Call us @ 866.305.4980 for any question you may have. Or better yet call me direct @ 949.485.1613 if you have a unique drain situation. Thanks for reading Jonny