Conserve Water! Convert Your Existing Toilet Into a Water Saving Dual-flush in 10 Minutes

Convert your existing toilet into a dual-flush toilet with nothing but a nylon lock nut.

Making an instructable for this was an afterthought, so I apologize for not having step-by-step photos.

This summer I decided to try and reduce our water usage in our toilets.

We have three 1.6Gpf / 6.0Lpf toilets throughout the house.

My first thought was to use the old 1/2 gallon milk jug in the tank trick. Upon opening the tank, the space was so small, I knew this wasn't going to work.

I shortly considered using a couple of bricks, which might have fit okay, but I really wanted to reduce the water usage more than that volume.

I wanted to reduce water consumption to approx 1 gallon per flush.

After studying the mechanism a bit, I thought I might be able to modify the float valve system to suit my needs.

This proved to be very easy to accomplish.

What you're trying to do is to adjust the angle of the float ball so it closes the tank fill-up valve sooner as the ball floats on the water.

This involves bending the rod and anchoring it with a lock nut.

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Step 1: Turn Off the Water to the Toilet Tank.

Next, flush the toilet to drain the tank.

Step 2: Unscrew the Float Ball From the Metal Rod

Unscrew the plastic ball from the end of the metal rod.

Be careful with this step, as you don't want to damage the plastic valve assembly.

Most likely the treads will be corroded a bit and it might be a little stubborn, so use a pair of pliers to grab the rod while you unscrew the ball.

Step 3: Screw the Metal Rod Completely Into the Plastic Valve Assembly

The rod will eventually be anchored from rotating by a nylon lock nut in another step.

But since we're dealing with plastic, simply cranking down the lock nut to prevent the rod from rotating might damage the threaded plastic valve assembly.

So what you're doing in this step is threading the rod as far as it will go, that way when the lock nut is screwed on, the rod will be less likely to loosen up and rotate in either direction over time.

You may be able to just skip this step if your lock nut will hold the rod whether it's screwed in all the way or not. This will also allow you to rotate the rod for minor adjustments once the ball is reinstalled.

Again, the threads may be corroded. So be careful not to damage the plastic valve assembly.

Use a pair of pliers to gently assist and work the threads loose.

Screw the rod in as far as it will go until it's snug, but don't over do it - remember they're just plastic threads.

Step 4: Mark the Rod With a Sharpie

This step is the most tricky.

Since we will be bending an angle in the rod, we need to mark the top of the rod with a short reference line down it's length so we can bend the rod in the proper direction once it is screwed all the way onto the valve assembly.

This is where you'll need to do some trial fitting for clearance.

The rod will be bent about 10-15 degrees downward. This should give you an idea of about where the ball will ride when connected to the end of the rod.

Make sure you plan to bend the rod so the ball will not rub against any of the toilet innards.

Put a mark on the rod about where you think the apex of the bend should be.

Step 5: Bend the Rod

I found that the rod bent easily. You can use your knee or thigh to help massage the bend.

Be careful, the rod is relatively soft metal.

It's always easier to bend it a little bit at a time, than to unbend it if you've gone too far. (ask me how I know)

As you work, stop and screw the ball onto the end and test fit everything to verify the angle you want.

Please keep in mind, that whatever angle you choose to bend the rod, it will still need clearance to be spun back into the valve assembly. If you bend it to much, it may hit the side of the tank when you go to screw it back in.

Step 6: Install the Lock Nut

Find yourself an appropriately sized nylon lock nut that will thread onto the end of the rod.

I can't remember what size mine was, and they may vary between tanks anyway.

Make sure you use a nylon lock nut for this instructable.

When I first had this idea, I used a regular nut and everything seemed to work fine for a few weeks until I heard the toilet running. The nut had loosened and the rod had rotated so that it was now in a "V" position...which was actually using more water than before.

I threaded my lock nut onto the rod with the nylon insert facing away from the threaded plastic valve assembly. I figured the fatter end of the nut would have the most friction against the valve assembly in this direction.

Threading the nut nylon end first onto the rod can be tricky. It helps to flip the nut around and run it onto the threads "normally" once or twice to "cut" some threads into the nylon insert.

Step 7: Reinstall the Rod and Float Ball

Thread the rod back into the plastic valve assembly. Don't tighten the lock nut at this time.

If you've bent your angle correctly, you should be able to thread the rod on until it's snug and the ball should have clearance to freely move up and down once it's threaded back on.

Screw on your plastic float ball.

Before you tighten the lock nut turn the water back on and let the tank fill.

Now you can make any small adjustments by rotating the rod if necessary.

You can also fine tune the water cut-off by adjusting the screw on the plastic valve assembly.

Carefully tighten the lock nut against the plastic valve assembly, being careful to not allow the rod to rotate. Again, be careful not to over tighten - you can easily crack the plastic.

Step 8: Test Flush

If you've done everything correctly, the ball should raise and lower with each flush without contacting anything in the tank.

It's also nice to notice just how much water you're saving with each flush when you look at the old watermark on the inside of the tank!

Believe it or not the toilet is now a dual-flush.

For liquids, simply press and release the flush handle like you normally would. The toilet should give you a clean flush completely evacuating any liquid in the bowl.

For solids, simply hold the handle down for a few seconds for a more complete flush which will use all the water in the tank. If one flush just doesn't cut it, you can always flush a second time.

Happy flushing!!!!

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    16 Discussions


    6 years ago on Introduction

    Trying to conserve water that way could end up costing you money,the water saver type toilets many of which dont flush well right after installed ,dont need anything to restrict the water they need for a half way good flush.Getting a good used 3.5 gal.toilet is really the way to go,your not saving water if you have to flush twice or even three times to get the stuff to go down.So you run the risk of a stopped up toilet,or worse a stopped up main line.Its like those water saver shower heads,it takes the same amount of water to take a shower and get the soap off,which only makes your shower time longer when using a WS shower head.Ive been plumbing/drain cleaning for 25 yrs. and alot of crap they claim saves water or money,is a crock.


    7 years ago on Introduction

    I just wanted to share an alternative since it worked for me...
    I molded and attached a piece of plasticine (about the size of a golf ball) on top of the flapper valve as a means to add weight to it.
    So now I can flush for as long as i hold the handle down (short time or long time), and the water stops flowing as soon as I release the handle. The rest of the toilet mechanism works as usual... Very cheap and no tools needed... Hope someone finds this useful to save water.


    8 years ago on Introduction

    Not all toilets are equal in performance, so reducing the water on a slow toilet only makes it worse. You will have to do more multiple flush to get the solid stuff down the drain defeating the goal. However for the liquid only visits it may be adequate. This is not a criticism, but an observation.


    8 years ago on Step 8

    So by dual-flush you meant "not dual flush." Haha. Most modern toilets I've worked on (not that many) the duration of your flush doesn't matter as the flappers are designed not to close until the tank has almost completely emptied whether you are holding the handle or not.

    Nice easy instructable, just found the title misleading!


    10 years ago on Introduction

    I just put a 3/8" nut through the chain, and sitting on top the flapper valve. Works like a charm.


    No need to bend the rod, instead use a spacer in the valve system for an earlier cut off, on some systems a few washers or tape wrapped around the rod will do.. Unless I've missed the exact point of the 'ible...

    2 replies

    Good idea. Never tried it though. Although I think that simply replacing the screw with a longer one might be easier and provide similar results.

    Yeah that'd work for the more common ones, I've had a few that just have a little bar that get pushed but the arm... Same principle... Also below, yeah people have trouble understanding some stuff...

    Infrah Rhed

    10 years ago on Introduction

    BTW, the photos are a little deceiving, the water level looks much lower than it actually is.

    Infrah Rhed

    10 years ago on Introduction

    I find it funny, folks telling me my toilet doesn't flush and it clogs...:) It doesn't.


    10 years ago on Introduction

    invalid movie:
    1. A regular toilet is not designed to flush paper and solid waste with reduced amounts of water, so the likelihood of clogging or having to flush twice increases. If you are serious about saving water, want a toilet that really works and is affordable, I would highly recommend a Caroma Dual Flush toilet. Caroma toilets offer a patented dual flush technology consisting of a 0.8 Gal flush for liquid waste and a 1.6 Gal flush for solids. Caroma, an Australian company set the standard by giving the world its first successful two button dual flush system in the nineteen eighties and has since perfected the technology. Also, with a full 3.5” trapway, these toilets virtually never clog. All of Caroma’s toilets are on the list of WaterSense labeled HET’s and also qualify for several rebate programs currently available as well as LEED points. Please go to for more detailed information or visit to see why they actually work so well. Best regards, Andrea Paulinelli
    1 reply

    10 years ago on Introduction

    This isn't a dual flush. there is a reason a toilet has a tank on it instead of just running water directly into the bowl. The force needed to defeat the trap and clean the bowl is more than water from a pipe can handle.

    2 replies
    Infrah Rhedbeerboyone

    Reply 10 years ago on Introduction

    Forgot to mention...depending on how long you depress the handle, it indeed flushes with more or less water.


    10 years ago on Introduction

    Saving water is always a great idea, but I'd like to put in a plug for a new toilet. I know it costs more than a washer, but speaking as an engineer, your bent float rod does less good than you would like to think. The problem is lowering the water height lowers the flushing force. Low water height with a standard "swirly" toilet may never generate enough rotation to develop "suction" that would pull the contents out the bottom. Along with other improvements to the flow path, the new toilets are specially designed to raise the water level in the tank as high as practical to maximize the flushing force through the bowl. You really have to see them to believe it.

    The design improvements over the past three years are like moving from horse and buggy into the space age. These new toilets have been designed by engineers with computers rather than by plumbers waving their arms and guessing at the right thing to do. These new toilets flush amazing amounts of stuff with 1.6 gallons. The entire flush takes 3 seconds and with the new refill valves, it is ready to flush again in 30 seconds. The other great feature is that they are much quieter than previous toilets.

    When I got my American Standard Cadet 3, there were only three toilets on the market that were of this new technology. Now there are probably 100 brands and models. The AS Cadet 3 is around $180 with seat at Lowe's and HD. Others are probably much less while the Toto brand is well over $400.

    Many of the new toilets have special glazes that will not support mold or bacterial life. They come in all shapes, sizes, and colors. Check out this website for 55 pages of results of a joint Canadian and American study on toilet flushing performance.