Slow-Flushing Toilet Q&ASlow flushing toilet diagnosis & repair FAQs #2:
This article series will help you diagnose and repair toilets that flush too slowly or have a weak flush, or that are backing up.
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These questions and answers about slow-flushing or poor-flushing or incompletely-flushing toilets were posted originally
at TOILET FLUSHES POORLY - please be sure to review the poor-flush diangosis and repair advice given there.
Also see our index to all slow toilet flush questions and answers at TOILET SLOW FLUSH FAQs
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Tip: If your toilet wants to overflow, see our emergency steps to stop it
When toilet flushes, it refills to rim, them suddenly empties to a level below usual refill line. at this point, tank is full to usual level. had recent replacement of innards after flapper problem when toilet flushes, it refills to rim. On 2019-12-26 by olivia
by (mod) -
Olivia usually when I see that toilet flush pattern there is a drain clog.
It's not likely to be a flapper valve problem because even if "too much" water were being sent into the toilet bowl during a flush, if the drain were not clogged that water would simply drain out fast enough to avoid filling the bowl to the top.
Our toilet flushes waste away just fine, but sometimes the bowl fills, then the water recedes, many times all the way down and we get gurgling. On 2018-03-08 by AWilson -
Reply by (mod): Clear and inspect the main building drain line to remove a remote clog
You're describing a toilet with a blocked main drain or, less likely, a blocked vent line.
When some flushes work normally but others are sluggish and water backs up in the toilet bowl, or worse, overflows onto the floor, I suspect that the blockage in the waste pipe is some distance away from the toilet.
So on the first flush that works normally, the wastewater and sewage flow into the empty section of the sewer line.
But because that line is partly clogged some distance away, when you run more water or flush the toilet again soon, before the wastewater has had time to seep through or past that partial blockage, the drain line now fills up with wastewater and sewage, causing the toilet to back up into the bowl.
Sometimes, if the drain blockage is close to the toilet, you can free a clogged toilet by plunging for a longer time than you thought necessary - give it more time and effort. But if the blockage is some distance away from the toilet, you need help from a plumber.
So if plunging the toilet doesn't fix the trouble, it's time to call a plumber who can run a toilet auger snake through the drain to clear it.
I would also have the sewer line inspected for damage using a sewer line camera.
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My toilet tank fills up to the normal level, however, the toilet bowl does not. The bowl only fills up about 1/3 full of water. The only way I can get the water in the toilet bowl to fill up to the normal level is if I turn off the stop valve and immediately turn it back on.
After a flush, refill tube and overflow tube appear to be working properly, as does the float ball. Could there be an issue with the flush valve and/or flapper? I've noticed a bit of fine gray sediment which has appeared in the very bottom of the toilet bowl. Are these related to my problem? On 2017-02-10 by Frank
by (mod) - adjustments and one repair determine the volume of water left in the toilet bowl after a flush:
Frank:
There are several features and adjustments and one repair that dominate the volume of water left in the toilet bowl after a flush:
1. the flow rate and quantity of water sent through the diverter tube into the top of the overflow tube during tank-fill:
(See our photo just above). On some toilet fill valves the tube may be crimped or the flow rate poor due to clogging in the valve itself, or of course on some the tube may be out of place and not sending water into the bowl
2. the duration of the fill cycle and water pressure and flow during that time
3. the adjustment of the lift chain on the toilet flapper and the volume of water that is thus sent into the bowl during the flush
4. a clogged drain line: slow flush may consume more of the bowl water
I'm not sure what sediment you are seeing: I'd consider replacing the fill valve assembly and flush valve. Inexpensive and a good bet if there's no sign of clogging and if water pressure is good.Below I show an example of a toilet flush tank diverter tube that had become disconnected; its water is sent into the toilet flush tank when it was meant to be sent into the toilet bowl as the tank re-filled. '
By short-changing the water went into the toilet bowl the toilet may lack enough "starter water" in the bowl to flush properly.
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Just repaired inside of my toilet. My problem is that the when I flush it only half of the water flushes.
That is, I have to hold the handle down until the toilet flushes completely. (Mar 26, 2015) Anonymous
Reply: shorten the pull chain on the flapper valve
Anon
It sounds as if your flush valve is not properly adjusted - perhaps the pull chain is just a bit too long.
If the toilet flush valve or flapper is not lifted up fully it may close early, stopping the flow of water from the cistern into the toilet bowl. The result is not enough water in the toilet bowl and a weak flush.
We fix this by tightening the pull chain that lifts the flapper to be sure it's lifted all the way up.
Some toilet flush valve flappers actually contain an adjustable dial right on the flapper valve, as I show below.
By holding the bracket part of the valve and rotating the dial clockwise towards a higher number you can increase the time that the flapper says "up" - thus sending more water into the toilet bowl.
As a default I usually install this Fluidmaster No. 502 Adjustable Flapper toilet flush valve when I'm repairing any flush toilet that uses a flapper type tank valve.
See these
Hi there,
I have had a slow flushing toilet for years, I've come here as a last resort before I spend some of my hard earned savings on hiring a plumber to replace it.
I have three 20 year old toilets, the toilets in the basement and the third floor work great. The toilet on the second floor does not. I keep it very clean and over the years I've tried the following thing and repeated them again this morning:
I've tried the bucket test and the water drains quickly
I've adjusted the water line to slightly higher
I've tightened the flapper chain
I've moved the styrofoam float closer to the flapper
I've checked all of the holes (jets?)under the seat. They seem clean. I gave them a poke with a wire coat hangers but not much came out.
I've tried plunging and checked the main jet.
All of things things have helped marginally, it's gone from really bad to just bad.
The only way the toilet works is if I hold down the handle for about 30 seconds. With just a regular handle movement, the flush starts fairly strong but quickly peters out. Even with the flapper adjustments, the flapper still seems to close too soon which slows down the flush considerably.
Is there anything else I should try?
Is it worth calling a plumber
Should I just pay someone to replace it (since I don't have these skills myself)?
Much appreciated! Joanne On 2016-11-05 by Joanne G
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by (mod) - diagnose weak flush toilet problems, don't just replace the whole toilet. Check these 3 things:
There is normally NO reason to replace an entire toilet just because it flushes poorly. Worse, the new toilet may flush poorly too if the problem is the drain or vent.
If the problem is NOT in the drain or vent piping then the problem is with toilet adjustment
Key in your description is
The only way the toilet works is if I hold down the handle for about 30 seconds.
That tells me that the toilet flush voume is not enough OR that the flapper valve is closing too early - as we discuss in the Q&A just above;
The handle on an American standard toilet wont raise the float. Seems like the suction is too strong for the handle to raise. On 2019-09-19 by bob
by (mod) - toilet flush handle won't raise the flush valve flapoper
Or likely the chain is too long or the connection to the flapper valve defective or the handle is actually slipping in its mount and needs to be replaced.
Also see details at TOILET FLUSH HANDLE LEVER REPLACEMENT
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How do I fix a toilet tank that fills back up very slowly?
My monther's tank started filling very slowly. At first, if I shut off the water supply to the toilet & turned it back on, if would fill normally.
Now sometimes it will fill normally & other times it will fill slowly.
I replaced the toilet's inner mechanisms less than 10 yrs ago and haven't had a problem since. But this seems to be more related to the supply and not the toilet itself.
What do you think? On 2016-11-20 by Anonymous
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by (mod) - slow filling toilet cister
Simplest fix, assuming that building water pressure is good at fixtures, is to replace the toilet fill valve assembly; The old one may be worn or clogged.
After I flush the water slowly keeps seeping into the bowl until the box manages to fill to the appropriate level then the seepage stops. What will cause this to happen?
To add to the question below it can take up to 5 mins for the tank to fill due to the water leaking to the bowl. I'm surprised that it no longer leaks when the tank is full. (June 29, 2015) Bob
Reply:
Bob
It is normal for some water to continue to flow into the bowl as the tank or cistern re-fills after flushing a toilet.
If you lift the tank lid you'll see a small tube that connects the fill valve to the top of the tank overflow tube at the tank center.
Water will discharge through that tube into the toilet bowl during tank re-fill cycle in order to assure proper bowl water level for the next usage.
Separately, the slow toilet tank fill may be due to clogging of the fill valve itself, toilet supply piping, toilet water supply valve position, or low building water pressure and flow rates.

My poorly flushing toilet problem was solved with the dishwashing detergent tip; then increasing the water level in the tank should help keep things moving along.
This is one of the best "how to" sites I have used. Thank you
Above: the toilet flush tank or cistern usually contains a mark indicating the proper fill-line or water level in the flush cistern. (Sept 11, 2014) Anonymous
Reply:
Thanks for the feedback Anon, it will assist other readers.
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