Toilet Keeps Running? Replace the Flapper!
If the water in your toilet is running intermittently or if it sounds like the water in your toilet won’t stop running, then the most obvious cause is almost always the toilet flapper. I had this happen to me recently and thought I’d explain how I fixed it.
The more a toilet runs when it’s not flushing, the more you are wasting water and racking up your water bill. Replacing that cheap toilet flapper is a simple DIY plumbing project that could save hundreds of dollars in water bills over the years.
My old toilet flapper. The curled and worn lip seal around the flapper edge was leaking and causing my toilet to run intermittently.
The toilet flapper is that little rubber gasket at the bottom of your toilet tank that is attached to one end of the chain or lever which extends up to most toilet handles. It helps if you understand how a toilet works. Most standard American toilets are pretty straight-forward devices: they have a tank which holds water and a bowl with some odd bends in the pipes beneath it. The toilet flapper sits between the tank and the boil. A toilet works with the help of gravity. When flushed the water from the tank pushes into the bowl with enough force to push everything through the bends of the pipes under the bowls.
That’s why toilet tanks are almost always above the bowl: they need gravity to work. The tank behind the bowl can then fill up with water again. Even if you have low water pressure, the toilet tank will eventually fill and you’ll have enough water in the tank to once again flush everything down with force.
The toilet flapper essentially serves as a sort of “trap door” that keeps the water in the toilet tank and then opens and releases all that water when the toilet is flushed. The flap door (toilet flapper) then closes shut again, allowing your toilet tank to once again fill with water.
If your toilet is constantly running, or even intermittently running, without you flushing it, then you have a leak somewhere. Water leaks are never good news, but some are more dangerous than others. Toilet bowls can crack, seals can break and water can leak. First look around the wall and floor area of your toilet, looking for any soft spots, puddles, or water damage. If you see any you have some serious problems and will probably need to replace the toilet and fix some water damage. If you don’t see any water leaking outside the toilet, the leak is most likely inside the toilet.
So how do you fix a running toilet with a leak inside it? You fix the leak, and the flapper is the first place to start. Toilet flappers are usually made out of rubber or soft plastic and are designed to “seal” the hole at the bottom of your toilet by having the weight of the water above them “push” them tight. This works great when the toilet flapper has a snug fit, but because most of these flappers are made out of soft material for sealing, they are also prone to wearing down and dry-rotting or degrading over time. Toilet additives like those bleach tablets can hasten damage and wear on a flapper. When the toilet flapper begins to wear out little streams of water will slowly leak into the bowl, decreasing the water in your toilet tank until it triggers the weight mechanism in your tank to run more water to keep it full.
You can test to see if your flapper is leaking or not fairly easily: put some non-staining colored liquid in your toilet tank and wait to see it start running. When it runs, see if you can see the colored liquid in the bowl below. If you do, then it’s definitely your toilet flapper that’s leaking. You can pick up some cheap toilet leak dye
Here, then, is how you can fix a running toilet with a leaky flapper:
1. Turn off the water supply line to the toilet. That’s usually a little silver knob or valve behind or under your toilet which controls the flow of water into your toilet. Once you think it is turned off, flush your toilet. If it flushes and the tank doesn’t refill, you found the right knob. If your toilet starts running and filling with water, then you might have to turn off the water somewhere else in the house. Alternatively, you could somehow “trick” your toilet into not running anymore by tying or propping up your toilet tank float, making it seem as though your toilet tank is full. Either way, flush your toilet and empty as much water as possible from your toilet as possible.
2. I usually now use a plastic cup and I scoop the majority of the remaining water from the toilet tank and just dump it in the bowl. I’ve found that most toilet tanks still have some water in them after flushing. Try to get as much water out as possible so you can expose the toilet flapper. Yes, toilet water is usually very cold.
3. Now look at your flapper. If it’s worn or old or simply not sitting right, then you’ll have to replace it. If you happen to know your toilet brand then you can sometimes just buy an American Standard toilet flapper or a Kohler toilet flapper or a Gerber toilet flapper or even a Toto toilet flapper. My house was built around 1950 and my toilet is originally, so I have no idea what brand my toilet is. Even if you know your brand I’d recommend taking the flapper out and going down to your local hardware or home improvement store. It usually just pops off the valve seal at the bottom of the tank. You might want to take along the chain or rod that’s attached to the toilet flapper just to be sure.
4. Go to the plumbing section of the home improvement store and you’ll find a whole wall of DIY plumbing and toilet repair items. Your best bet is to try to find a toilet flapper that the most closely resembles the toilet flapper you had. Pay special attention to the back or hinge portion of the toilet flapper because those have to match the seat at the bottom of your toilet tank. Other than the brand names, there are some general all-purpose toilet flappers that fit a variety of toilets. Toilet flappers usually cost less than $10, so fixing your constantly running toilet is a pretty cheap repair.
5. Install your new flapper in place of the old flapper. Attach the chain or lever and do some “dry flushes” a few times to make sure everything seems to be working. The toilet flapper may not automatically go down, but that’s okay because most are designed to work with a tank full of water above them, not just dry air.
6. Once you’re satisfied that the toilet flapper is installed properly, turn on the water (or untie the toilet tank float) and let the tank fill with water. Cross your fingers and flush the toilet, but pay special attention to how the flapper works. Is it opening enough? Did a full tank of water get flushed out? Is it closing properly? You may need to adjust the chain or lever tension or length to make sure everything is working just right.
There you go! For a few dollars you can pretty easily replace the toilet flapper in a toilet that’s constantly running and wasting a lot of water. Your toilet should now only run when flushed thanks to that new toilet flapper.
Comment by Dennis
I am living in Greece. I have a leaky flapper. The part doesn’t exist in Greece. So I am stuck. What do you recommend? Could you send me the part and I will pay you. Or whaterever you recommend.
Frustrated.
Comment by Tom
If you can’t find anything local then I’d probably suggestion you try buying a toilet flapper online
through a vendor like Amazon.com that will ship internationally. You’ll want to compare the photos of the toilet flappers on the web pages with the flapper you have now. Good luck!
Comment by jami
Did I do it wrong? I put several cups of coffee in the tank – which turned it brown – and waited. The water in the toilet didn’t turn brown, but there was a little silt (like fine coffee grounds?) in the bottom of the bowl. However, I then checked the water in the tank, and it was clear. Where did the coffee go? Does that also suggest a leak? Thanks!
Comment by Tom
Jami, if you saw grounds in the toilet bowl then they definitely went down, but if you didn’t see the water in the bowl turn brown with coffee at all then there are two options: 1 – your tank is leaking water/coffee all over the floor (you would probably notice that) or 2 – your coffee was diluted too much dripping into the bowl and you simply didn’t see it. If grounds got into the bowl WITHOUT flushing, then, yeah, your flapper is most likely leaking and that’s probably why your toilet runs from time to time – to refill the tank with the water that is seeping into the bowl…
Good luck!
Comment by Alex
I have been having problems with my toilet running, so I replaced the “innards” of my toilet tank. I am not sure of the names of the parts, but the flapper was not what needed to be replaced – a new flapper came with the kit I bought, so I went ahead and replaced it anyway. The original problem was fixed, but NOW my toilet runs because of a leaky flapper – the new one was a somewhat flexible but still stiff flapper, whereas the old flapper was a very soft, VERY flexible material. My mistake was throwing the old parts away, since I assumed the new ones would work just as well… Now I cannot find a soft flapper like I need anywhere in stores. I have tried several different kinds of flappers, but none of them work! The only ones I can find are hard plastic or semi-flexible materials, but I cannot find a truly soft flapper like my old one. Any idea where I can find a soft flapper?
Comment by Tom
Alex,
I don’t know of any place special where you could find a “soft” flapper for a toilet, but I know exactly what you mean. I have two bathrooms in my house and one has a flapper that’s made out of a more flexible and softer rubber while another seems to be made out of a hard plastic or something. The semi-flexible rubber seems to work for me…
My local mega-hardware store has a bunch of different toilet flappers to choose from, though most are packaged so you can’t feel if the flapper is hard or soft. A plumbing supply shop might have an even bigger selection – you could probably check the phone book for a local one.
I installed a flapper on one of my toilets a while ago that didn’t work very well – it leaked a little bit when closed and tended to “hang” open a little too long. In theory the water in the tank should weigh down the flapper and keep it from leaking, but after you first flush there is no water in the tank to hold the flapper down tight.
My solution in that case was simple: I took a few pieces of lead fishing line weights and sealed them into the top part of the flapper with a little rubber plug I glued in. I probably could have just taped a quarter to the top, to be honest. Either way, the added few ounces of weight seemed to solve the problem: no more leaking and the flapper didn’t “hang” open any longer…
Heh… about the comments: it’s cool. I moderate comments so that I can publish the real comments and keep out all the spam comments. So I have to go through and manually approve all the non-spam comments every couple days…
Good luck!
Comment by Liza
Hi Tom,
I got problem with my toilet tank which is water keeps running from my toilet bowl. I’ve done everything as what you advice. But none of them works. But, i noticed that my water feeder knob is not function anymore. Do you think that is the main cause?
Comment by Tom
Liza,
You mean the little knob on the wall behind your toilet? That allows water to go into your top toilet tank. If that wasn’t working at all then you’d either have water on the floor or no water in the tank at all. Without being able to see the situation, it’s difficult to tell what else could be leaking or need to be replaced in your toilet. Or do when you say “water keeps running from my toilet bowl” do you mean the bowl itself isn’t keeping water in it?
Comment by Michael
Hey Tom!
I followed your suggestions today and changed ONLY the flapper after my toilet suddenly started to leak with intermittent flushing. This did the trick with only $4.91 (tax included)of Korky Plus brand from Home Depot.
In my situation, I think my problem was with the old flapper.
Thanks for saving me a possible $60.00 plus for a professional service.
Comment by maria
we have replaced the flapper, but the toilet still runs forever after its flushed. it looks like the flapper is in place what else can we check for? jiggling the handle doesn’t work either
Comment by Tom
Maria,
Well, if the water is running there’s only three things that can really happen:
1. The water will continue to run until the cut-off switch is activated (usually with a float mechanism of some sort) and the water stops running when the tank is filled to a certain point. This is the way it SHOULD work :-)
2. The water will keep running and the toilet tank will overflow. That’s rather uncommon, but it does happen. You would notice that.
3. The water will continue to run and never get high enough in the tank to shut off inflow of water. This can only really happen if the water going into the tank is also going OUT of the tank some where. If you don’t have puddles of water on the floor, then it almost has to be going out through your flapper mechanism.
If you’ve already replaced the flapper then you may also want to check the sealant ring or gasket around the drain in the bottom of the tank (it’s the hole that is blocked by the flapper).. Maybe that’s dry rotted or has some leaks in it.
Another way to test if your flapper or gasket is leaking: flush the toilet, let the water start flowing back in and then either take a long stick or ruler or something and press down firmly on the flapper, doing your best to make sure it seals tightly. You could use your hand for this, but toilet water is pretty darn cold, so you might end up freezing your fingers. If your toilet tank fills and the water stops flowing while you are pressing down on your flapper, then it’s almost definitely a leak down there.
When you remove the stick then your toilet might start leaking water again and then water might start flowing in again.
Good luck! Let me know what you find!
Comment by Lisa
I replaced the fill valve of my toilet and with that kit came a new flapper. I shouldn’t have thrown the old flapper out but did. When I flush, the flapper gets stuck in the up position and I need to giggle the handle to get it to drop. This wouldn’t be a problem if the toilet was in my bathroom but it’s in my 16 year old’s and she “doesn’t hear it running” so she doesn’t giggle it which means when I hear it I have to holler up to her to giggle the toilet. Short of taking the flapper off and widening the holes that go over the ears on the fill tube -somehow….what else would you suggest doing to make it fall more easily? Thanks.
Comment by Tom
Lisa,
First, make sure the chain or rod from your toilet handle to your flushing mechanism (some attach right to the top of the flapper) has enough slack in it to let the flapper float and drop freely.
I’ve also seen toilet flappers “float” a little too much and then have a hard time coming back down. Take the back of the tank off and maybe check to see if an air bubble is forming in the bulbous part of the flapper. You may want to try adding a little weight or maybe somehow sealing up that flapper hole so air doesn’t get in. It isn’t easy to do because the flapper spends most of it’s time underwater. Your best bet may be to simply the same sized toilet flapper that is designed a little better.
Hope this helps!
Comment by Bill
I replaced my toilet flapper because water kept running but I notice that the float as it drops lands on the side of the flapper keeping the flapper from dropping all the way and sealing causing it to run water.(The problem I thought the flapper would fit) Is there a simple adjustment here or do i need to replace the float also. Any help would be appreciated!
Comment by Tom
Bill,
It’s hard to say without actually seeing exactly how all the pieces in your toilet are designed, but if I had to guess I’d say: fiddle with everything you can find first. If you can’t get it to work reliably then you’re better off going with new parts.
Comment by Judi
I have a 5 year old Gerber toilet in my basement. I went downstairs today and I saw that the bathroom was soaked in water and water seeped under the molding into my den area. After trying to figure out where the water was coming from, I found out the toilet is running at times without being flushed. It goes over the water piece that fills up the toilet and keeps running, hence, the overflow. It does not have a ball adjustment, seems it’s controlled from a pump.
If I adjust the pump to make it stop filling, a few minutes later the water starts going down and then reaches a point and starts filling up again. Obviously, I have shut off the water valve otherwise I’d be having another flood.
Can this be fixed my me or do I need to call a plumber?
Thanks,
Judi
Comment by Tom
Judi,
So… the water is flowing out of the tank and not the bowl? That sounds like you need a new float system. It sounds like something is not, as you correctly guessed, switching the water off when the tank is filled to a certain level. Most of these float switches are just mechanical devices that can get wear out due to corrosion or other “gunk” that may collect.
If you’re not comfortable replacing the float system (I’ve found that it’s sometimes easier to replace all the parts at once than to try to find one specific piece) then you definitely may want to call in a plumber. But, hey, ask if you can watch how he fixes it so that next time you’ll have a better idea of what you’re doing! It’s a shame about the flooding… good luck!
Comment by Allen
Thanks for your guide. I have a leaky flapper which I replaced with a very similar-looking one from home depot. My problem is that it isn’t creating an airtight seal when it’s attached to the hinge. If I remove it from the hinge and let it sit flat on the outflow opening, it seems to make a seal, but the moment I attach it to the hinge, it seems to upset the even seal. Is there a smart way to ensure a good seal in this kind of situation?
Thank you in advance!
Comment by Riz
Changed the flapper to a universal flapper however water has been leaking from the knob on the wall. Any suggestions?