View Full Version : toilet bowl leaks to empty in 30 min, starting at normal level

10-22-2012, 08:45 PM
Are there any other possible causes of a bowl leaking down to bone dry in 30 minutes, other than a clogged vent, or a possible leak in the internal trap itself?

Zero moisture shows up in the ceiling below.

Tips appreciated.

10-22-2012, 09:20 PM
Something like dental floss wicking the water out.

I would be thinking it's more likely a bad bowl though.

10-23-2012, 12:54 AM
Do you know if this toilet was added after the house was built?

When was the last time you had the main drain line from your house cleared with a snake or jetter?

If the answers to those questions are yes, and a very long time ago, then I'm thinking you need to have the main drain line from your house cleared.

Where I live, if you add a toilet to your house, you don't have to provide any venting for it; you just tie it in to the vent stack (provided it's within 10 feet of the stack) or just connect the drain piping to the main drain line from the house.

But, if that main drain line is partially clogged with solids (mostly from the kitchen sink) then the flush water may just be filling up the drain piping behind that partially clogged section.

Then, as that backed up water slowly drains away, you get a vaccuum created behind the draining water, and that partial vaccuum sucks the water out of the bowl.

Maybe test to see if that's what's happening; flush your toilet and wait for the bowl and tank to finish refilling. Now, push a short piece of vinyl tubing into the large discharge hole at the bottom of the bowl. Stick the tubing in far enough so the end is above the weir at the back of the bowl. Blow into that tubing to clear any water out of it. Now, air can flow through the tubing to relieve any partial vaccuum in the toilet drain piping. If doing that prevents the bowl from losing any water, you know the bowl water is being sucked out.

(Maybe do something to ensure that tubing isn't flushed into your drain piping if someone flushes that toilet inadvertently.)

10-23-2012, 02:47 AM
It would be hard to siphon the bowl dry, wicking would likely take longer than 30-minutes to empty a bowl, so it's probably a defect in the bowl. An internal hole could allow the water to just go down the drain, and not exhibit a leak onto the floor.

10-23-2012, 06:40 AM
The toilet was plumbed when the house was built. Nothing new here, except the dry bowl.

No recent main line cleaning, though all other toilet bowls hold water just fine, and flush normally.

The clear tube idea seems like it is a good one, and you'd probably want it to be 1" or larger, as trying something smaller likely may still allow some back pressure, against some suction.

It seems that an equal possibility might be a clogged vent.

A potential drawback to both theories, as Terry pointed out, is the DRY bowl. One would think that if the bowl is being emptied due to suction - you would expect some water left in the bottom of the bowl - and we have none.

10-23-2012, 09:03 AM
For the time it's gonna take, why not do the hose test, and if the water still disappears, then you know that suction isn't even a part of the problem.

If the water still disappears with the hose in place, I'd take the toilet off, and set the bowl alone on a 5 gallon pail. Fill the bowl with water until you hear water spilling into pail so you know the bowl is full. Now add some food colouring to the water in the bowl. See if the water still disappears, and if it does, what colour the water in the pail is.

10-23-2012, 09:21 AM
People here have shown pictures of a factory plug repair that failed...it is nearly impossible to suction a toilet totally dry - a bad vent won't do it! Wind or a back-to-back situation can cause it to rock, and thus allow some to spill, but that will NOT empty the bowl. The only way to empty it is if it has developed a crack or a hole has appeared. Again, wicking, such as from something like dental floss, can lower the water level, but to get ALL of it out, you'd have to have it plugged so it got caught, and part of it would have to be sticking out in the bottom of the bowl...lower the level, yes, empty, NO.

10-25-2012, 08:07 PM
It appears that it is leaking through a hairline crack on the bottom of the internal trap. Zero damage to the subfloor etc.

Don't you know this would happen on a $500 one piece black toilet.

I know it's not recommended, but I'm curious what experience others may have had with applying epoxy to a small crack in Vitreous China. It's either that or pitch it, I suppose. Unless there is another glue or sealant which would work. Like 3m 5200 polyurethane marine sealant.

I'm aware that plumbing pros are likely to say just pitch it, but since this is a DIY site, maybe there will be more openness to other solutions.

Don't laugh, but it's a fact that some composite and metal parts of some aircraft wings are held together with epoxy. :)

Gary Swart
10-25-2012, 09:20 PM
I doubt if there is anything that will work, but you certainly can try. You are right about many things being held together with high tech epoxies, but as a toilet patch, I don't know. I don't see where you mentioned when the house was built, but if it was before low flow toilets were mandated, this really would be the time to consider a new toilet. Most of us on this forum highly recommend the Toto brand as they are very efficient and trouble free. Some models are in the $200 range. A toilet is a pretty easy DIY install.

10-25-2012, 10:52 PM
Personally, I'm a big fan of epoxy repairs. A pretty fair percentage of my daily ride consists of fiberglass and epoxy, where the original metal has sadly been
consumed by rust. The stuff is perfectly waterproof, and very durable, even when exposed to the elements. Aside from determining the exact extent of the
crack(s), the only difficulty I see is possible adhesion problems to the slick porcelain, so I think you would do well to roughen the area up with sandpaper. Two
or three layers of fast-setting epoxy and fiberglass cloth should do it. The epoxy and cloth should be available at almost any hardware store, and you could
color the epoxy to match with carbon black, available from concrete/stone supply houses, art supply stores, etc. You'll want to smooth any roughness down
with sandpaper after it sets up: not a good place to have snaggies.

10-26-2012, 12:27 AM
There are industrial sealants that would work, but you need to buy them in bigger quantities, and they tend to emit nasty fumes, AND cost LOTS of money. Prep of the surface is critical, and keep in mind that cracks in porcelain often grow. Since this didn't leak originally, something caused it to crack (uneven floor, got knocked hard, a defective casting, etc.), it happened. When it does grow, the next time it starts to leak, you may not be so lucky and it ruins things while you're away on a 2-week vacation. Don't take a chance, replace it. Leaking water can cause thousands of dollars of damage; and, it doesn't necessarily take very long.

Gary Swart
10-26-2012, 01:48 AM
Just bear in mind that low flow toilets are not created equal. Some of the famous old name brands do not produce the best quality toilets anymore. You won't find a good one at a discount store unless you are extremely lucky. Read over the comments in this segment of the forum.

10-26-2012, 05:14 AM
You won't find a good one at a discount store unless you are extremely lucky.
Just what do you mean by "good one"?

10-26-2012, 06:44 AM
quote; You won't find a good one at a discount store unless you are extremely lucky.

You will find even fewer "good black" ones.

Gary Swart
10-26-2012, 11:47 AM
What's a "good" toilet? Of course, "good" is a relative term, but what do you want from a toilet? Most of us want a toilet that will flush everything in one flush, that will rarely, if ever, clog, that will have no physical defects, and that will be inexpensive to maintain for many years. The reality is that Big Box Stores frequently have low quality toilets that appeal to builders and budget conscious homeowner. Frequently these toilets have defects from the factory that are sold at a big discount to the Box Stores. Many have poor internal designs that preclude reliable flushing and are prone to frequent clogs. Sometimes repair parts are not available or are available only from the manufacturer at a very high cost. Even some plumbing supply stores sell well known name brand toilets that are still poorly designed even after years of low flow mandates. How do stores get away with this? The average homeowner does not study and research toilet quality. We tend to rely on the well known, highly advertised names who at one time did produce quality but have merged and been outsourced overseas with a resulting loss of the quality they became famous for. So, can you tell by looking at a toilet if it is good or not? While those that may have a factory defect can often be detected, those will poor internal design will look just fine. The Toto line is the only line that appears not to have the problems mentioned above. Less than 1% of Toto toilets will have a defect. All have superior internal designs so many Toto owners don't even own a plunger, and all Totos use standard, off the shelf replacement parts. While some models have advanced features resulting in a high price, even the basic standard Toto Drake performs like we all expect a toilet to perform, and costs about the same as many of the old big name brands. Lest you think Toto is a small, upstart company, you should know that Toto is the largest manufacturer of toilets in the world. They have plants in several countries, including the United States. (Georgia) When the low flow mandate became law, many of the old line companies tried to tweak there existing water hogs to use less water. The result was disaster and gave low flow a bad name. Toto realized from the beginning that modifications to the mechanics would not work and set about rethinking the toilet's internal design. So how can you tell a "good" toilet? Buy a Toto and know you have a good one.

10-26-2012, 02:24 PM
In addition to Gary's excellent post, I would mention that Toto has readily-available toilets in Ebony, which is what they call black. Just do a little research. Always check several prices because dealers vary widely in what they charge, and the biggest dealers usually have black in stock.