A Letter to Carlo #1: How To Change A Toilet's Fill Valve

I started writing this post in a straight forward manner. Then, as I was outlining the steps in my notebook, I realized that this DIY was something I needed to teach Carlo someday. One thought led to another and we have the first of a new series on the blog: Letters To Our Children. This series will be an ongoing journal or time capsule for anything and everything that we want our kids to learn or read on the blog later when they’re older. So if you want to learn about repairing a leaky toilet (which interrupted the Great Purge happening around my home), read on… If not, that’s okay too.  

Dear Carlo,
At some point in your life, your toilet may start “running”. Whaaaat? Yes, running. That’s the proper term for it. Or so I’m told.

Know that you don’t always have to call a plumber to fix this problem. Chances are you can do it yourself. I did! And before I came to live in Canada, I never thought this was something I could do by myself.

I figure that by the time you’re old enough for me to teach you how to do this, you may roll your eyes at me, groan, and possibly whine an overly, angst-filled statement like, “Aw, Mamaaaa! Do I have to???? I’m watching ________”. So I’m saving myself from future drama, and I’m saving you from future boredom by writing this post.


When a toilet has a leak, it could be because the water filling up the toilet tank doesn’t ever seem to shut off; hence, the water is always “running”. In my experience with our toilets here at home, the problem was due to either the flapper or the fill valve being worn out.

The leak may not be obvious because the water (and the noise of the tank filling up) does stop eventually. But if you notice that it’s taking longer and longer before the water/noise stops; or you see that there’s always water streaming down the insides of the bowl, then chances are you may need to replace the flapper or the fill valve.

Ask your papa sometime about the night he waged a war with our toilet downstairs. That’s how we first learned about running toilets, gunky flappers, and broken fill valves.

First, you should check if your flapper needs replacing…

1) Lift the toilet tank’s lid and check if the flapper was dislodged. If it was dislodged, adjust the flapper’s “ears” and realign the flapper so that it covers the hole correctly. If the flapper was not misaligned, go to step 2.


2) Check if the tank’s water is NOT near the top of the overflow tube. There should be about an inch clearance from the top of the tube and the water line. If this is fine, go to the third step. BUT if the water level is almost to the top of the tube, it’s the fill valve that needs changing.


Do yourself a favor and shut off the water to the toilet at this point. Do this just to be safe and to prevent the toilet from possibly overflowing and possibly flooding the house (one of your papa’s worst nightmares). Water coming to the top of the overflow tube (hence the name of that tube) is NOT a good thing.

If you can, don’t use the toilet anymore (especially if there’s another toilet in your home.) If not, take time to go to Canadian Tire or Home Depot and buy a fill valve. The one Papa bought last January cost $12. I don’t know how much it will cost you by the time you actually deign to dig up this post of mine; but, it’ll definitely cost you less than paying a plumber to fix it for you.

As for the time it takes to replace the fill valve, I would put it at 30 minutes tops. Unless the nut under the tank is seriously stuck; then, it may take you longer.

3) Mix up some watercolor (I used your water-based finger-paint) or food color in a cup of water. Any color is fine but make sure to make it quite strong or dark. Actually, even that blue Lysol cleaner would do or heck, you could brew a cup of tea. Then, pour the mixture into the tank. Now, walk away and come back after 10 minutes. If the water in the bowl has streaks of color, then yes, your flapper needs to be changed (even if it looks okay in step 1 above).

How to change the fill valve…

You will need a set of groove joint pliers (the one in the photo below is a pair that I should’ve given to you, if not, ask me for them); some old towels or rags to mop up any spills or leaks; a bowl/basin to catch the water as you disconnect the water supply hose; and work gloves (optional), because when I first changed a fill valve, the nut under the tank was screwed on so tight, I had friction burns on my fingers and palm from gripping the pliers as I tried to loosen it.


1) Position the basin under the shut off valve. Turn off the water supply to the toilet tank.


2) Flush the toilet to drain the tank. Other web guides say to use a sponge to mop up the water that is left in the tank. I didn’t bother; hence, the basin.

3) Unscrew the first nut, the one connecting the water supply to the tank.


4) Using the pliers, unscrew the second nut, the one connecting the fill valve to the tank.


5) You now should be able to take out the broken fill valve.


6) Read the instructions that come with your new fill valve. The model we bought had an pull-and-click-to-adjust the height of the valve. It also has a screw on top to regulate the water line level in the tank. I don’t know what models will be available in the future and what features it will have; so, please listen to your mama and read the instructions. Thank you.


7) Use the height of your old fill valve as a guide for the new one.

8) Plop your new fill valve in place. Connect one end of the supplied hose to the fill valve and the other end to the top of the over flow tube.


9) Tighten the fill valve’s nut, usually supplied as well, underneath the tank. Just use your hand at first.


10) Reattach the supply hose and tighten that nut also by hand.


11) Turn the water to the tank back on. Adjust the water level to your liking by adjusting the floatation mechanism on your fill valve. Remember to leave at least an inch clearance to the top of the tube. Flush the toilet a couple of times to check if all is well.

You’re almost done!!!

12) Place some paper towels on the floor, underneath the tank, right below the hose and nut section. This is Papa’s idea which is really smart; because, if there are any leaks from the toilet tank, the water drips will leave blotches or crinkled spots on the paper towels after the wet spots have dried. Walk away and come back after around 20 minutes.

If you find blotches on the paper towels, tighten the two nuts a bit more with the pliers. Not too much though because the nuts are plastic and over tightening will crack them. Then, you can replace the paper towels with a new batch and do the check all over again. But I would bet that your toilet is now leak free!


Ok, Carlo-bug, you can go watch TV now. You did great!


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