Toilet water in bowl slowly drains minutes after flushing has completed

**Voyzey** · 08-05-2005, 11:17 AM

The water in my toilet bowl drops very slowly minutes after a flush has been completed. The water in the bowl won't empty completely but it does drop considerably lower than right after it completed flushing. It has me a little puzzled because there isn’t any leak anywhere around the bowl or tank and the water in the bowl does eventually stop dropping after a while. I installed a new FluidMaster Flush Valve & Flapper over the weekend but that didn't fix the problem.

How do I get the water in the bowl to stay at the height it's at right after completing a flush? Is this a DWV problem? A couple of years ago I had a bird caught in the pipe. It eventually turned up inside a toilet!!! My first experience with a clogged vent!

Could a blocked vent be the cause of this problem again?

Any help would be greatly appreciated. Thank you!

**Terry** · 08-05-2005, 04:25 PM

Water in the bowl is based on the height of the bend of the trapway.
Water will drain over the "dam" until it's even with the top.

If the water is lower than that, it could indicate a leak or crack in the bowl.

**Voyzey** · 08-07-2005, 02:06 PM

Thank you for replying to me! If you don't mind me asking a couple more questions...do you have any insight as to where the leak could be? I don't have any water around the bowl on the floor. Is there a test I can perform to be certain it's a leak? I'm pretty sure the bowl filled higher and kept the water height years ago before I encountered this problem. Thank you!

**plumber1** · 08-08-2005, 04:48 PM

Make sure that the small refill tube is connected to the overflow pipe by using the metel clip. That keeps the refill tube above the top of the overflow pipe and by the time the toilet shuts off, the bowl should be up to its overflow point. A partially plugged sewer may cause water to lower in the bowl. also I have seen a sand hole in the china casting let water drain down. The toilet was several years old. I found it when I turned the bowl upside down. Was able to fill hole with an epoxy. Again,check the refill tube..........

**Voyzey** · 08-08-2005, 05:58 PM

Thanks for your help! I checked the small refill tube and it's definitely connected to the overflow pipe correctly - just above the top of the overflow pipe line. Water still seems to be dropping after the flush has completed though. Looks like I'm relegated to removing the toilet and checking for leaks, huh?

**plumber1** · 08-17-2005, 12:40 PM

If you pull the toilet, turn it upside down and look for a pinhole like spot that might have a little rust streak near it. I've seen it twice. assumed that there was a thin spot in the china when it was cast because the toilet was a few years before this leak showed up.

**Kristi** · 08-17-2005, 02:36 PM

I had this issue, and was surprised by the fact that this toilet drained itself of every last drop of water in the bowl. The problem? A pressure assist bowl installed with a regular 6L flush tank...

**plumber1** · 08-18-2005, 03:52 PM

Is this toilet on a slab?

**slicey** · 08-22-2005, 05:57 PM

Originally Posted by plumber1

Make sure that the small refill tube is connected to the overflow pipe by using the metel clip. That keeps the refill tube above the top of the overflow pipe and by the time the toilet shuts off, the bowl should be up to its overflow point. A partially plugged sewer may cause water to lower in the bowl. also I have seen a sand hole in the china casting let water drain down. The toilet was several years old. I found it when I turned the bowl upside down. Was able to fill hole with an epoxy. Again,check the refill tube..........

"Make sure that the small refill tube is connected to the overflow pipe by using the metel clip. That keeps the refill tube above the top of the overflow pipe and.........."

could you clarify.....in the above excerpt, do you mean the clip holds the refill tube in place so that, when the toilet is flushing, water from the refill tube is directed into the overflow tube? I'm clueless as to what purpose the refill tube serves. Would you explain using the good image from post #2
thanks slicey

**SteveW** · 08-22-2005, 06:18 PM

Originally Posted by slicey

"Make sure that the small refill tube is connected to the overflow pipe by using the metel clip. That keeps the refill tube above the top of the overflow pipe and.........."

could you clarify.....in the above excerpt, do you mean the clip holds the refill tube in place so that, when the toilet is flushing, water from the refill tube is directed into the overflow tube? I'm clueless as to what purpose the refill tube serves. Would you explain using the good image from post #2
thanks slicey

I'll jump in here. The purpose of the refill tube is to "refill" the bowl after a flush. Without it, the water level in the bowl would be a bit lower than the maximum it could be (refer to Terry's graphic above) due to siphoning action during the flush. The fill valve directs most of its water into the tank, but a small part of it goes down the overflow tube and into the bowl to "top it off."

**slicey** · 08-23-2005, 12:11 AM

thanks, SteveW, now i know.

**master plumber mark** · 08-23-2005, 04:10 AM

it might be an idea here to just go out and buy some

green or blue food coloring and put some in the bowl

to siphon out on the next flush.....

let it sit for a day or so and eventually if their is a hiair line crack

in the trap , it will leave you a line in the china to seee....

if or when you take up the bowl to see what is going on with it....

their can also be sometihing like a mop string caught on the trap
wier of the toilet hanging down into the drain , this will make the toilet
siphon down the its water...

maybe you might want to just get a toilet auger and shake things
up a little bit first....

enjoy......

**kstutrud** · 09-09-2010, 05:25 AM

Just curious what the problem ended up being?

I installed 2 American Standard toilets last month. One is fine, the other one loses its bowl water after a minute or two. I can flush and the bowl fills ok, but within a minute the water level siphons down to almost exposing the hole in bottom.

Refill tube is positioned correctly in tank.

Help!

hj · 09-09-2010, 05:41 AM

A crack in the bowl that causes the water to drain out is seldom where you can see it. In many cases, the problem exists for a long time, but a leaking flapper, or other source of water, continually compensates for the lost water. It is only after the toilet is repaired and the leak fixed, that the problem becomes evident.