How to Repair a Leaking Toilet
If you discover you have a leak in your toilet, don’t wait to get it checked out. As much as 80,000 gallons of water can be wasted each year by an undetected toilet tank leak. That’s more than 200 gallons of water going down the drain each day. Watch this video to help diagnose why your toilet is leaking … and how to fix it.
- Pencil or Marker
- Food Coloring
- Colored Fabric Softener
Remove lid from tank.
Pour several drops of food coloring or a cap full of blue fabric softener into the tank.
Wait 10 minutes.
Inspect water in bowl to see if there any signs of color from fabric softener or food coloring. If so, the toilet has a leak.
Shut off water to toilet.
Mark water level in tank with marker or a pencil.
Check back after 10 minutes to see if water has fallen below mark. If so, the leak is coming from the flush valve. Watch the video How to Replace a Flush Valve for more information.
If not, check to see if the leak is coming from the fill valve by examining overflow tube to see if water is running into tube. If so, watch video “How to Replace a Toilet Fill Valve“ for more information.
Read Video Transcript
Did you know that as much as 80,000 gallons of water can be wasted each year by an undetected toilet tank leak? That’s more than 200 gallons of water going down the drain each day. It’s not good for the environment and it’s not good for your wallet, either. The good news is that it’s usually an easy problem to fix yourself.
Today, I’ll give you the project basics that address the most common problems with toilet tank leaks to help you get started before you head to your local independent home improvement retailer. That’s where you’ll find everything you need, including the tools and materials, , and the right know-how, to complete this project on your own.
There are two common problems that generally cause a toilet to leak-either a problem with the flush valve which looks like this) or a problem with the refill valve (which resembles what I’m holding here).
Since minor leaks many times go unnoticed, an easy way to determine if your toilet leaks is to pour some food coloring or blue laundry fabric softener into the toilet tank when it is fully refilled after a flush. Give it a couple minutes and then inspect the toilet bowl for signs of color. If the water in the bowl is blue, you know there’s a leak.
But before we start troubleshooting whether your leak is coming from a flush or a fill valve (or a specific component), if the internal parts of your toilet look like they were made twenty years ago it will save you time and money in the long run if you replace all of the toilet tank components at once. It doesn’t take that much more time, and most toilet repair parts manufacturers make complete replacement kits with everything you need for around $20.
You’re also going to need some tools to complete this project, so be sure to click the Tools and Materials checklist button to for a complete listing of everything you need.
If you discover you have a leak and the parts in your toilet tank look relatively new, then you should first determine if your toilet problem is with the flush valve or the fill valve. This takes a little more investigating, so let’s get started.
The most common cause of a leaking toilet tank is when the flapper fails to seat properly and form a tight seal against the valve seat. This lets water leak from the tank into the bowl. It may be caused by the flapper being out of position. It might also be caused if there is a mineral build-up on the bottom of the flapper that prevents it from “seating” properly. If you see a scaly build-up on the bottom of the flapper, shut off the water and drain the tank by holding down the flush lever until the tank is completely drained. You can remove the scaly buildup with steel wool or fine sandpaper. You can also buy a new replacement flapper for a few dollars.
As the water leaks out of the tank and into the bowl, it is then replenished by the fill valve, causing a continuous flow of wasted water. To check for this, first shut off the water supply to the toilet. Mark the water level in the tank with a pencil or marker, then check it again in 10 or 20 minutes. If the water level has fallen below your mark, the flush valve is leaking. If not, the flush valve did not leak, and you know that any leaks are being caused by the fill valve.
If the fill valve isn’t working properly, the tank will generally overfill through the overflow tube, and the excess water will continue to run into the toilet bowl. This is usually either caused by a waterlogged float or when the water level is set too high. A good rule of thumb is to set the water level about 3/4″ below the top of the overflow tube.
If your fill valve has a threaded shank to adjust the water level, push the lock ring up and turn the shank to adjust the height, which will then adjust the water level.
If you have questions about this or any other home improvement project, be sure to read our list of Frequently Asked Questions for this video. And be sure to print out our Project Instructions, which includes a Tools and Materials checklist, before visiting your local independent home improvement retailer. That’s where you’ll find all the products and helpful advice to complete your project. If you’re not sure where to find your local store, check out our Store Locator.
Good luck with your project and thanks for watching
Close Transcript
Excellent and very easily explained video. Even i could do it after seeing the video! My wife will have a heart attack when I tell her that i fixed the toilet myself without calling a plumber!☺️
Our flush flapper at the bottom is obviously wearing at the edges. We replaced it ourselves about seven years ago and obvioudly, it was inferior. You can see tiny crumbs in the bottom and ragged edges. This time we are not able to do this ourselves and wonder how to get a fair price and using better product.
All flappers degrade – they’re made of rubber. Most usually last only 5 years or so. Just replace it again. Why can’t you replace it yourself?
what tools do I need to install all the internal assy kit?
thank you!
[…] will not want to deal with toilet troubles? It is one of the most irritating things once would regret to experience. Even for leakages or […]
[…] best way to determine a leak due to a faulty valve is to pour some food coloring into your toilet tank to see if the water in the bowl turns the same color. If you plan on replacing the tank components […]
Turn the water off. Flush the toilet to get most water out of the tank. Remove the old flapper. Use a rag to wipe the seal area clean of any buildup, especially on the inside of the seal. Replace the flapper with a new one that boasts of superior rubber or “longest lasting.” Works 90 percent of the time and costs very little. I am 75 years old and have had many successes with this .
Thanks for the concise instructions!
I made the mistake of putting one of those blue tablets in my toilet tank last week…all of a sudden two days a go the stuff is leaking out of the toilet bowl even after the flush is over. Hoping it is not clogged somewhere but I think that is what is causing my toilet to run and leak water into the bowl????
I replaced the flapper a month ago and the trickling stopped but it’s back again. It’s not the fill valve. What else can it be?
I had a newbie Repair nan replace the guts,cause the flap was ole. I’ve never seen anyone use a pipe wrench to do the w.He never demonstrated the toilet worked,however that night it wouldn’t flush. The next day,he said it was fine…Ireland is water leaking opposite side underneath where a bolt is(opposite the flush handle) it’s constantly dropping EVEN WITH THE WATER OFF!
My tank of the toilet is leaking about two cups of water onto floor overnight. There is no fault to the flapper or fill valve. I replaced these. When it still leaked as much onto floor, I replaced the whole toilet with its new parts. It is still leaking. I find that the bowl is not as full as originally, although the wax ring is new> HELP.
If water is dripping onto the floor, then it sounds like you have a leak from where the toilet tank mounts to the bowl – there are usually screws that mount the two together; sometimes over time and if the bolts are overtightened, small cracks form in the bowl – water can eventually leak out of here. Happened to me several years ago; water dripped so slowly I didn’t notice for months..
Sounds like it’s leakijg from where the tank mounts to the bowl? Try to check if the bolts are tight enough / if there are any cracks in the hole in the tank.
This is great, you explain stuff so well and provide great solutions and steps to follow.
Thanks
I replaced the valve seal, but for some reason it’s not sitting right and water is still leaking. I’ve tried adjusting it to no avail. Any idea of how I can fix this?
Hi I put one of those blu loos in my toilet cisten and it says that it should last around 4 weeks but within a couple of days the blue water has disappeared and i have quite a larger water bill this time, suggesting that I may have a leak. How would I check as it’s not leaking into the bowl, but somewhere else? (not on the floor either of course)
[…] repairs tend to get done on an as needed basis. If your toilet is leaking water all over the floor, for example, that’s something you’ll probably get fixed right away. If a […]
this is a newer model of toilet
Very helpful! Thanks!
Wow great blog post! I definitely learned some new techniques. Cant wait to try them out.
BTW Do you do windows lol. Thanks so much for the instructions it was very very helpful and trust me if I can do this anyone can do it.
Hi! my toilet tank was completely almost empty when I flushed the toilet and there is water all over the floor. I shut off the water supply. The toilet bowl is almost full. What seems to be the problem? need some advice. thanks.
We replaced all new insides afterwards we done the food coloring test it seemed to have fixed it but about 2 days later BAM the food coloring test showed we had a leaky toilet again why???
Hi,
Please suggest how to stop dripping from bathroom shower?
Regards,
Harry