How to Convert a Toilet to Dual-Flush – This Old House

This Old House plumbing and heating contractor Richard Trethewey shows how to save water without replacing the toilet. (See below for a shopping list and tools.)

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Full episode:

How to Use Graywater in Toilet Tanks:

How to Change a Toilet Seat:

How to Install a New Toilet Flange:

Shopping List for How to Convert a Toilet to Dual-Flush:
– dual-flush valve, for converting toilet to dual flush[BR][BR]
– fill valve, used to replace existing fill valve

Tools for How to Convert a Toilet to Dual-Flush:
– pliers, used to loosen nut on fill valve

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People Li says:

that is inconvenient

Connor Nelson says:

the fill valve was not broken

marcotoni231 says:

yo….does this nigga have a rat tail. hahahahahaha wtf classic

david goddard says:

I wonder why he didn’t show us the meter reading for the week after installation

Chilli-Billy says:

looks like someone’s been shitting in the cistern

Keelan Joyce says:

I am going to do this at home!!!

Jack Davis says:

They should have got one with the handle instead, the push button is awful mate. You can get these with the handle see.

George Ashing says:

half gallon milk jug works too it’s called water displacement


save more money piss in the sink and shower



Hiker Marapese says:

The combined cost of the duel-flush and fill valve isn’t a whole lot less than a new toilet as most water districts offer a rebate on a change out. As well, if your flush valve is old there’s a good chance your going to crack it when attaching the duel flush valve, more costs!

Atlas Shrugged says:

Stick a brick in there, don’t have to be Archimedes to know that.

Pete Brown says:

It’s been a LONG time since I saw anyone sporting a rat tail.

DarkRaptor99 says:

Ugh I slicked up my hand bad trying to replace a fill valve. The Treads were cross threaded and I thought I could snap it off bad idea gave myself a nice cut.. Rushing a project never pays.

People Li says:

my mom hate the push button

koolkevin1107 says:

Great video and explanation. However, It would have been smarter to just replace the whole tank. Here’s why:
1) Cost of dual flush – $40
2) Cost of new fill valve because old one wasn’t filling properly – $35
Total: $75 but you still have an old looking toilet that takes up a lot of room with that 3.5 gallon tank.

New toilet with built-in dual flush that only uses 1.6 gallons on a FULL flush and .6 on a half flush (from Home Depot): $130.

So all in all, great video, but I would have gotten a new toilet.

Ryan Hathorn says:

Daw look at his wittle pony tail!


I have never heard of a refill tube, maybe British toilets are designed better, looks far too much water in the bowl at the end talk about wasting water & you can adjust to have less than 3 & half gal

Pete Brown says:

I think it would have been awesome if he put a spoiler on top and new rims as well. 😉

Sonny Wright says:

How much water did you waste installing it!?!?

People Li says:

I want just change the valve

XzTS says:

Well, they do make the flush levers for dual-flush systems now…
Up for liquids, down for solids

Sam says:

I just installed a new fill valve… Goddamnit

David Levesque says:

My experience, sometimes there’s no way around having a dual flush. Many sedentary people need it. It’s not as simple as everyone having a water saving toilet.

Porsche924Tim says:

Recent bowls are designed to flush with more force. So by converting the guts of an old tank, you still have less than optimum force flow down in the bowl.  If you are going to use less water coming down from the tank, you really need a bowl that is designed with more flushing force to work properly.  A new toilet will be a better investment in the long run.

thechosendude says:

creepy intro, all zoomed up on their daughter…

Dakota Sheridan says:

I got that in all my toilets

Peter Knot says:

Who the F flushes his toilet 14 times a day? Maybe that’s why your bill is so high

orestesdd says:

Some people are complaining about the zip tie deteriorating over time, and thus causing a malfunction and wasting lots of water. I wonder why a plastic zip tie can deteriorate within just 6 months as someone claims at the home depot web site. Anyone knows or is aware of this issue?

FILIKU says:

Interesting. Cool tail

Tim Toolman says:

I installed this brand in one toilet and the Fluidmaster in another a few years later. The Fluidmaster is much easier to adjust. There’s two knobs you use to tune the amount of water just right to do the job. I had to remove the tank and replace the Flapper valve since it wasn’t compatible but in the end a great control and I like the up down handle better than the button. I doubt kids can remember which button does what so in the end they hit the large one every time. They may not remember the handle direction either.

san379 says:

THAT OLD TOILET IS STILL  A 300  TO 500 gram flush toilet.. blocked and plunger…  i bought a american standard  1000 gram flush toilet.. i took the plunger n threw it down the basement not needed 

JOe Shmoe says:

should be followed up with how to get rid of that dual flush cause it wastes more water than anything I ever had.  When you flush and not so much as a sheet of TP goes down that is 100% waste of water.  3 years and I have had it.

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