I noticed yesterday that my upstairs bathroom's toilet takes quite long to fill after flushing. That toilet is also constantly getting clogged; a source of endless drama when it comes time to plunge it. The actual bowl isn't overflowing, so it's not using as much water as it sounds like it is.

 After taking the lid off and looking inside, it takes nearly three minutes for the water to stop flowing into the upper tank. When it does finally stop, the level is below a ring of deposits that runs around the tank (old house, original plumbing), leading me to believe it's also not filling as full as it used to. None of the other toilets in my house have deposits or scale build-up, so I'm uncertain why this one does.

 Here's what I've tried so far, since I've really only been working on it since last night:

  • Checking the valve to see if it was—somehow—partially closed. Even fully counter-clockwise, the flow rate doesn't improve.
  • Raising the float to increase the water level. Nothing; I think it's partially waterlogged, but that shouldn't affect both the rate and and level, yes?
  • Spraying the hose, tubing, and intake valve with CLR to possibly remove any internal buildup of minerals. I'm letting it sit overnight for now, but my earlier attempt didn't provoke any results.
  • I read that there's a cover on top of the intake valve, and beneath that, the valve itself; that if your flow-rate is reduced, you should remove those and try to clean them. However, my toilet doesn't seem to have a removable cover on top. I'm not really even sure how the water exits, since it looks to just run down the float ball's piping from somewhere.
  • I also checked the rubber seal at the bottom of the tank, and the tension and position of the lever arm as well, but neither of those had anything wrong with them, and fiddling with them didn't change anything.
  • 1
    The rate of fill & the rate of empty are unrelated. What territory is this? What size pipe is feeding the cistern? When you say you 'raised the float' how was this done? What float/valve type is it? [pictures would help]
    – Tetsujin
    Commented Jan 23, 2022 at 12:49
  • Does the water pressure seem to be the same between the sinks upstairs and downstairs, when you open the faucets? Toilet parts for inside of the tank are usually cheap and easy to replace(faster than cleaning).
    – crip659
    Commented Jan 23, 2022 at 14:33
  • To answer you both: I understand the rate of fill =/= rate of empty, but the total amount being filled is also lower than other toilets, even on the same level; i.e. it's taking longer to do less. The piping is consistent throughout the house, and pressure doesn't seem noticably lower wherever I'm at: basement, ground, 2nd floor, it's the same. Unless I get a flow meter, it's undetectable to my eye. IDK why this 1 toilet is acting differently, but as suggested, replacement of internals seems the best/fastest fix. Commented Feb 6, 2022 at 8:55
  • Maybe it's just used more or closer to the water entrance to the building so it catches more junk on its way in?
    – rogerdpack
    Commented Feb 12, 2022 at 0:27
  • @rogerdpack Unfortunately, nope. This toilet is on the second floor, and it's only used by 2 people consistently. Plus, there's a combo shower/tub right next to it that runs perfectly fine. Contrast that with the ground-floor "lavatory" that probably sees 30+ butts a day, and works flawlessly. The only factor I can think of is that this bathroom—for whatever reason—is the only room in the house with a skylight. IDK why that would effect a closed toilet, but maybe? Humidity isn't any different either. Commented Feb 18, 2022 at 3:09

1 Answer 1


TL;DR Replace the toilet guts.

Something is clogged, but basically the parts - plastic, rubber and/or metal - all wear out over time, which can result in slow filling, incomplete filling, phantom flushing/filling, etc. Clogging can be due to insufficient water from flushing == incomplete filling. Trying to fix the little parts may be a short-term fix but may result in more problems, and the bottom line is that these parts wear out over time.

There are a variety of kits available. Most are relatively "universal" - i.e., including enough adjustment capability and/or multiple choices of key pieces so that they can work on most residential toilets made since the 1950s, at least in the US. But do read the details - some may be only for low-flow toilets from the last 20 - 30 years. A typical example from a major brand:

Toilet parts

If you have a local hardware store then you can look at your options and pick something. Some have more changes than others, though almost all do away with the old ball float. If that's not practical, order online after checking the details.

  • 1
    Your picture looks very similar to the product I have installed, though with better clip design. I started looking more closely, and it's heavily corroded/mineralized/congealed/nasty, so rather than disassemble a possibly 20+ piece of plastic, replacement seems the better option. I still need to figure out why only one toilet is in such bad shape, but that's the domain of a different question. Commented Feb 6, 2022 at 8:48

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