I have just moved into a new apartment and I found the toilet does not have a very powerful flush. After thoroughly cleaning the entire toilet – inside and out –, checking the water valve is fully open, and tank water level is correct, I still found the toilet to not flush properly.

I believe I have traced the issue to grime and dirt under the toilet rim that must be clogging the rim jets. I tried a few different household cleaners with a toilet brush as well as pouring vinegar through the overflow tube. I have removed quite a bit of the dirt; however, about 35% of the toilet rim still does not provide water when the toilet is flushed.

As many online guides suggest, I tried to use a mirror to look under the rim of the toilet and a wire to clean out the jet holes. However, the space between the bowl and the rim is quite narrow and I am unable to see any jet holes under the rim even when using a good mirror and flashlight. I do see a lot of dirt however and I cannot seem to get rid of it. Does anyone have any suggestions on how to restore full flushing to the toilet despite the hard to reach area under the rim? Is it possible that this toilet does not have any flush jets?

  • Has anyone tried pouring CLR (or equivalent) down the overflow tube, using a funnel to keep the CLR from spilling into the toilet tank? That should fill the rim with CLR, which should help dissolve the calcium build up.
    – user53461
    Commented May 3, 2016 at 15:45

5 Answers 5


I have horrible water, rust, iron etc. Someone told me to drain the tank. Then put duct tape over the holes under the rim. Add your cleaner of choice to the tank, (I poured directly into the bowl filler part as I was "flushing"). I used CLR. Let it sit for 30 minutes. Opened up the holes pretty well. Did it again. Flushes like new.


You need to get some sort of acid into the affected area. You can use vinegar, which is relatively safe but slow and relatively expensive. You could use citric acid, commonly available as a dry powder that you can add to water, and generally cheaper (per effective acid function) than vinegar. You can also use the nastier sorts of acid, some of which are pretty cheap, but generally more hazardous as well. Some commercial toilet cleaners have a significant proportion of hydrochloric or other acid in them.

I would lean towards citric acid, myself. Since it is difficult to get an effective application up under the rim, I'd shut off the water supply to the tank/cistern, add acid to the cistern and flush (either a very slow partial flush, repeated, or simply a full flush, depending how cheap you can get your acid or how much you care about the cost.) If the water passage in the rim is not totally blocked, this should apply acid to the top of the problem area. Let this sit in the passages of the toilet for a while (several hours, at least) and then repeat (or return to using the toilet normally until the next day before you leave the house, and repeat just before you leave the house.) Do make sure that pets can't get at it and any other people in the house know to turn on the water and flush the toilet before using it.

With dry citric acid you MIGHT be able to mix some with a tiny amount of water and effectively form a paste that you could get to stay up under the rim. But I have not actually tried that, and you would have to be quite careful with it as it would be very strong citric acid.

Another method would be to deliberately and reversibly plug the toilet so you can fill it right to the brim with an acid solution and let it sit and work for a long time. Something on the lines of a balloon stuffed in the bottom.

  • When I tried using the vinegar, it didn't seem to make it to the affected areas and drained out before doing much. The citric acid paste idea is interesting and I think I will try it.
    – Jono
    Commented Oct 20, 2014 at 23:36
  • would Coke work?
    – user24242
    Commented Oct 21, 2014 at 5:22
  • 1
    Coke® has a little bit of Phosphoric acid. It's also an rather expensive source of acid, and not terribly strong. So for limited values of work, sort-of. Certainly not what I'd reach for first, second or third.
    – Ecnerwal
    Commented Oct 21, 2014 at 14:52
  • Unrelated side note: My father is a doctor - and if I remember correctly -, when I was younger, he somehow got someone's tooth and put it in a cup of Coke. After some time, the tooth had visible deterioration. Yay acidic soda!
    – Jono
    Commented Oct 21, 2014 at 18:04
  • @bluet Coke would permanently stain the toilet, I would suggest against it.
    – Ariel
    Commented Jan 19, 2015 at 18:03

It's possibly, but highly unlikely. A more likely answer is that the house must have hard water (or have had hard water in the past.) This leads to iron, lime, calcium, manganese, and magnesium deposits.

I would suggest using one of the commercial hard water deposit removing substances- if I recall correctly, one's called CLR (for Calcium, Lime, Rust). The hard part is going to be getting the solution up into the area you need it. I'd try a foam scrubbing pad, soaked in the solution.

One caveat though, most of these mineral deposit removers are very caustic, use gloves and eye protection, especially if you're going to be inches away from them; and open a window for ventilation, too. If you have any pets, make sure they can't get into your cleaning equipment before it's had a thorough wash.


I just use an electric toothbrush (I use only for cleaning) with extra thick toilet bowl cleaner and a mirror. Takes about 10 minutes every 3-6 months depending on the time of year. (Well water) if it's completely clogged, I use a thumb tack to reopen the hole then insert a toothpick soaked in the extra thick toilet bowl cleaner.


Please follow safety rules: wear full protecive eyeware & long gloves and a source of washing area should you need to dilute your cleaning agent. (It does not cost much & you cannot get a second pair of eyes.)

For this job make sure you can do without using the toilet flushing system for several hours to allow CLR to work well. Make sure the toilet rim jets are well dry before you start to use the gaffa tape. You can still use the toilet by flushing with a bucket of water.

The best way to get CLR liquid into the toilet rim jet area is to block all holes with gaffa tape but leave one large hole vacant. You will need that hole to use it as a filling hole. I rigged up a 2L hydration bladder bag which comes with A tube with a rubber or silicon gromet with a hole slightly smaller than the tube. Fit the tube into the gromet and have it protrude a couple of inches. Insert tube and gromit up into the vacant hole to seal. Now fill the 2L hydration bladder bag with CLR and allow the liquid to flow along the tube filling the toilet jet cavity (you my have to refill the 2L hydration bladder bag again several times hoping to get that cavity fairly full). Leave that fluid in the cavity for several hours. Support the 2L hydration bladder bag to keep the CLR in the toilet rim jets.

After time has elapsed you can get rid of the water drainage in the toilet then remove all tape from the rim jet holes including the gromet with tube allowing the CLR and other debrie to fill the drain hole. Leave if you wish which will also clean the Drain. If the drain is clean then flush the toilet and watch the flushing action which should be good.

The way I have explained is that it will also get rid of black mold in and around the toilet rim jets. CLR is a calcium, lime, and rust cleaner which cleans various items. But still read the instructions for use. CLR or other makes can be purchased in the UK or USA.

  • Hello, and welcome to Home Improvement. This is impossible to read, and doesn't seem to be proportional to the problem. You should probably take our tour so you'll know how best to contribute here. Commented Feb 14, 2020 at 16:47
  • @DanielGriscom: The post is blatant spam. Just flag it and move on.
    – Chenmunka
    Commented Feb 14, 2020 at 18:02
  • Holy crap! Just buy a new toilet at this point!
    – gnicko
    Commented Feb 14, 2020 at 22:04
  • Use bleach which will do most of the work 4 you
    – Les Jones
    Commented Oct 13, 2022 at 13:07

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