Our apartment has extremely hard water, and the toilet has severe mineral buildup that makes it impossible to flush. Is it possible to attach a filter to capture this before it deposits on the toilet?

Edit: It's a brown stain, so I'm guessing it's not lime.

  • You need more than to toilets if that goes in .Sinks will be later .Need whole house filter .
    – user101687
    Jun 21, 2019 at 20:15
  • 2
    Typically manganese (&/or iron) for the brown staining, but quite common for it to be only part of the equation - it will happily stain the limestone that's also depositing brown if the water has both lime and manganese (&/or iron.) Manganese alone rarely builds up much, it just stains heavily. If the concentration is high enough, you should avoid drinking the water, but you'd need a water test to know how high the concentration is.
    – Ecnerwal
    Jun 22, 2019 at 2:45

1 Answer 1


The lime or other minerals are dissolved in the water, so no amount of filtering will typically help.

Solutions for hard-water involve treating the water in some way. Hard water creates many different problems, and usually toilets are the least-expensive issue. Killing your hot water heater is typically the most immediate side effect, and certainly you'll have scale buildup elsewhere in your plumbing that you don't see. As a result hard-water treatment systems typically treat the whole water supply for the house. There are a few main categories for the most common water-treatment systems:

  1. Water softening through sodium ion replacement (aka classic water softening systems)
  2. Reverse Osmosis (typically the most expensive option)
  3. Water chelation (a more modern method. By way of example this is a chelation system. I've never used it and I'm not advocating for it, it's just less familiar to most so I wanted an example).

In short, hard water sucks. If it is causing problems for your toilet it is causing problems elsewhere, and you might as well treat the whole house (which is pretty much the only option anyway).

Note for apartments: I can't imagine there are any jurisdictions where you would be responsible for fixing this mess. If your toilet is clogging due to build up caused by hard water, that's clearly not your fault or your responsibility if you are only renting. That's not to say that forcing management to fix it is easy, and, not being a lawyer, I'm not sure how this would collide with a lease provision that makes you responsible for clogs (although again, I can't imagine such a provision would apply to clogs like this anymore than it would apply to clogs caused by tree roots). Yell at management until they fix it. If they can't/won't, then it may be time to start apartment hunting the next time your lease is up.

  • 1
    Opinions vary, of course, but I don't regard a basic water softener as particularly expensive. I'd rather have water that does not need it, but if needed, not so terrible.
    – Ecnerwal
    Jun 21, 2019 at 20:42
  • @Ecnerwal I've never liked "typical" water softeners (mainly because of the slippery feel), so I'm probably just biased (I've also never bought any kind of water softening system). I've gone ahead and updated my answer to remove the implied "expense" of all the options, expanded it a bit, and left things more neutral.
    – conman
    Jun 21, 2019 at 20:49
  • @Ecnerwal I can't use one of the big whole house water ones in an apartment. I've been looking for a tiny softener to put just under the toilet, but I can't find one. Jun 21, 2019 at 21:20
  • 4
    Aside from complaining to apartment maintenance/management, if it's so bad it's making the toilet "impossible to flush" - (and they should then deal with installing a softener, or maintaining the one they may already have, but not maintain) the only "toilet-only" sized approach is to periodically add an acid to dissolve the lime buildup - various "lime removal" products are sold and I don't care to promote any, but they are all some sort of acid.
    – Ecnerwal
    Jun 21, 2019 at 21:37

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