How do I get a stronger flush from a low-flow toilet?

February 2, 2005 8:32 AM

Any good hacks for getting a low flow toilet to deliver a stronger flush? Commode replacement is not, unfortunately, an option.
posted by nakedcodemonkey to home & garden (15 comments total)

Unfortunately I don't know of a hack, but my plumber told me about a low-flow system that used compressed air to help flush. Supposedly it worked really well. HTH.
posted by petebest at 9:55 AM on February 2, 2005

This page has some pointers near the bottom...most of them involve maximizing flush capacity.
posted by bachelor#3 at 9:57 AM on February 2, 2005

This may be bullshit, and I freely admit I'm making it up, but it seems that if you reduced the diameter of the inflow pipe, it would increase the pressure. Maybe there are step-rings for that sort of thing?
posted by mudpuppie at 10:21 AM on February 2, 2005

I don't know how your toilet is built, but some of them limit the water per flush by blocking off a portion of the tank from filling with a large plastic cylinder. I have heard these can be removed thus providing much more water per flush. You will no longer have a low flow toilet but if you don't have to flush it two or three times to get it to work you may come out about even.
posted by caddis at 11:04 AM on February 2, 2005

I've always thought moving the tank higher should help, but this involves quite a bit of Toilet Surgery. I would also test extensively before cementing the pipes in place, I have no idea how much of a 'raise' you'd be able to get before the water starts to jet out of the bowl...
posted by daver at 11:17 AM on February 2, 2005

It's a rental, so the options are somewhat constrained here. The landlord is going to be cranky, for instance, if surgery is done to his toilet or pipes.

Caddis, I think you may be thinking of a common hack to convert an older toilet to low flow. An object such as a brick or plastic container is placed in the tank to displace some of the water so that there's less available to use per flush. Whereas this toilet is one of the models designed to use a miserly amount of water. The tank doesn't appear to have any obvious displacement object in there.
posted by nakedcodemonkey at 11:36 AM on February 2, 2005

Low flush toilets use different techniques to limit the amount of water. Some use the cylinder I described above which surrounds the flapper valve and limits the amount of water which flows to that amount which fits within the cylinder. Good thing you don't have this as it probably would not be a good idea to take this out of a toilet in a rented apartment. Some toilets use a special flapper valve which shuts early. Watch when the toilet flushes to see how long the flapper stays up. If it closes long before the tank empties it is the flapper valve which limits the flow. Some have holes (which you might be able to plug) and some use floats. This article describes how to modify one with floats. Some toilets limit the flow into the tank from the ballcock valve. If your tank seems to only partially fill that is probably how flow is limited. These work different ways but you may be able to adjust this to get the tank to fill higher. Some toilets use fancier systems such as pressure assist but these should work well enough even at 1.6 gpf. I am not sure of the legality of making any of these modifications so modify at your own risk (and perhaps your landlord's).
posted by caddis at 1:15 PM on February 2, 2005

Caddis, thanks for the explanation. That helps clairfy things. I watched the tank go through a flush cycle as you suggested and lo and behold--the tank is filling to barely half-way! Then leaving 1-2" of that still in the tank. Maybe 2-3" of water in total (a gallon, at most?) is making it into the bowl. No wonder the pressure is so lousy. Judging by the water lines, the tank's previous water level was at least 3/4" higher, and has dropped several times from a peak level that was 3 whole inches higher. Sheesh.

So does that mean that bachelor#3's link to flush optimization techniques are the place to start? Or the float mods page? The mechanism, by the way, looks very similar to this, though with a round rubber contraption over the drain instead of that blue thing.

posted by nakedcodemonkey at 2:44 PM on February 2, 2005

a) When the water stops, is the black cylinder on the left (the float, which moves up and down with the water level) right up against the bottom of the grey cap? If not, you can raise it by squeezing the silver tab (far left in the picture) and sliding the float up the silver rod. That tells the toilet how much water is in the tank. Keep sliding it up and down until you get the right level (there should be a mark inside the tank that says 'water level'.
b) If that doesn't work (say there isn't room to raise the float) you can raise the entire ballcock (that whole contraption on the left) by popping the white ring up and wiggling the ballcock gently upwards, until the top is just below the rim of the tank, then slide the white ring back down until it snaps into place. This is easiest if you shut the water off at the the little tap near the floor, behind the toilet and then flush. Less wet and cold.
I hope that's not gibberish
posted by towerbrave at 3:25 PM on February 2, 2005

What towerbrave said, although I think some of them have a screw thread for adjusting how high the float can go. Also, in that picture the top of the overflow tube, the big one on the right with the clear tube going into it, looks pretty low. If that is the case in your toilet you will need to find a way to make it higher as the water level can not be any higher than the top of the overflow tube.

Each system is a little different and you need to figure out how it operates and then you can start fiddling. If you find yourself really befuddled you might try heading out to your local hardware store, HomeDesperate or whatever and ask about how the particular mechanism in your john works. They may even give you pointers on disabling the low flush aspects. Good luck.
posted by caddis at 3:39 PM on February 2, 2005

The black cylinder is only going to half-mast. There's definitely room for it to go up several more inches, but there doesn't seem to be a way to adjust it upward permanently. The clip on mine seems to serve as a guide for the cylinder's movement along a wire rod. No visible way to raise the wire, or fix the cylinder to a higher position on it. Not without taking off the lid and reaching in there before each flush, anyway.

The ballcock is just above the rim already, so no go on that.

The water levels off way below the overflow tube, and is about 1/2" above the highest water mark on the porcelain.

But this is good. I'm learning about toilets. Any more hints?
posted by nakedcodemonkey at 5:07 PM on February 2, 2005

The black cylinder is only going to half-mast.

Something is preventing it from going all the way up and you need to figure out why. First, try adding water to the tank from a bucket and see if it goe up any higher. If it does than something other than the float is controlling how much water comes in to the tank and I have no clue as to what it might be. If it stays under water as more water is added to the tank then there is a physical block to the float which you must find and eliminate or raise.
posted by caddis at 5:38 PM on February 2, 2005

If you lift the black cylinder does it slide up and down on the little metal rod? That would suggest that the clip is busted -in which case you probably need a new ballcock.
posted by towerbrave at 6:16 PM on February 2, 2005

Towerbrave, yes it does slide up and down on the rod. Thanks!
posted by nakedcodemonkey at 9:09 AM on February 3, 2005

Low-tech solution: keep a pitcher near the toilet, and fill it from the tub and pour into bowl with each flush.

I did this at a former rental house.

It uses less water than flushing several times.
posted by yesster at 12:31 PM on February 3, 2005