How To Repair A Toilet

The Handyguys talk about the dirty side of home improvement — well, unless you clean it regularly. The toilet is something nearly everyone owns (unless you live in back woods Appalachia), and everyone has to address the persnickety problems presented by a toilet.

When a toilet fails, you may be left with a water bill that is 10 times higher than normal. Before you have this kind of problem, it is a good idea to learn a little about how your toilet works.

Tan, fill valve, flapper, flush handle

The toilet is composed of a bowl and a tank. Within the back tank, where the water reservoir is located, you will find two main components (just lift up the lid and look inside). The first component is the fill valve.

This valve is connected to your house water via a short section of hose or pipe which connects to the fill valve at the bottom of the tank. This short hose or pipe is normally connected to a shutoff valve on the wall, which feeds water to the toilet. Older houses may not have this shutoff valve because it was not in residential codes a long time ago.

The fill valve’s duty is to add water to the tank when you flush. As the water rises in the back tank, a float rises up and turns off the fill valve at the proper time. Hopefully!

The other main component in the tank is the flush or flapper valve. This valve opens up when you flush to allow the water to flow down from the tank into the bowl.

Trap from outside.

Another important component that is more difficult to see is the trap underneath and in back of the toilet bowl. This trap keeps sewer gases from coming into the house. It also keeps the water in the bowl and helps to create a siphoning action of the water when you flush to suck out all the “debris”.

Now let’s address the problems common to toilets. The biggest problem is a toilet that leaks. In most cases you will hear the refilling when it is not being used, but in some situations there will be no auditory warning (thus a big water bill). How can you tell that the toilet is leaking at all and that your big water bill is not being caused by long morning showers?

The simplest method to diagnose this problem is to put dye, such as food coloring, into the water tank. After putting the dye into the tank, come back in an hour or so to see if the colored water has migrated down into the bowl (the water will remain clear in the bowl of a toilet that is operating correctly). If the colored water has migrated to the bowl, you have a leaking toilet. There are two possible causes for this leak. The more common reason is that your rubber flapper valve is leaking. This is the valve or stopper at the bottom of the tank that lifts up when you flush the toilet. When the toilet is not being used, it should prevent any water from flowing down into the bowl. If this flapper fails, your fill valve will keep refilling the tank as the water level recedes. Normally you will hear this when it happens.

If your flapper valve is failing, you can often fix the problem by cleaning around and under the flapper. In some situations, grit builds up underneath the flapper, preventing a good seal. On occasion, you can provide a long-term fix by cleaning the area on the bottom of the tank where the rubber flapper makes this seal. If cleaning does not work, you can easily replace the flapper for a few bucks. The Handyguys like the newer Korky flush valves, which can be found at the big box stores. Be sure that your new flush valve fits correctly. Test it by flushing the toilet to determine if the new flapper has a good seal. Also, lift up the float so that the tank fills up over the overflow tube, and confirm that the water runs through the overflow tube without running over the top of your tank. Paul has seen a situation where a wrong-sized flapper valve constricts the flow of the overflow tube and prevents it from working well.

Once you learn how to replace the flapper, it is like changing a light bulb. If you have hard water, you may have to replace it every year.

The other possible problem related to large water bills is when the fill valve is failing and slowly and continually adds water to the tank. You may not hear this when it happens. When you have this problem, your dyed water will run down the overflow tube in the tank and into the bowl. But how do you determine that the fill valve is the problem? One way is to mark the water level in the tank with pencil right after a flush and a tank fill. Make sure that your water is turned off when you do this test. Check back after 30 minutes and see if you water level has receded. If it has, your problem is probably with the flush valve as we stated above. But if your water level remains the same, then most likely your problem is with the fill valve. The water is continually running through the faulty fill valve into the tank and going over the overflow tube.

Supply line

How do you fix a fill valve? You can replace it completely or you can replace its washers (on some models). If you want to replace it completely, it will only cost about $15. Just turn off the water and flush the toilet to get the water out of the tank. You may want to use a sponge to get all the remaining water out. Remove the supply tube that connects to the bottom of the tank — it is connected with a large nut.

Again, make sure the wall valve is off before performing this operation! Since many toilet wall valves are not reliable, the Handyguys often turn off the entire house water before doing this procedure. After loosening the large nut, there is normally a smaller nut that connects the fill valve to the bottom of the tank that releases the fill valve unit. You can now lift the fill valve out of the tank.

Another problem you may face is that your tank fills up too high or too low after a flush. Normally the water height can be adjusted. With newer toilet parts, there is a float attachment as part of the fill valve. This float device can be raised and lowered accordingly to get the correct water level (most toilet tanks have a mark to locate the proper level). On older toilets, there is usually an arm attached to a float bulb. You can often just bend this arm some to make the adjustment of the water level.

What do you do if you discover that the toilet is leaking water onto the floor? This sort of leak could be caused by a bad hose connection to the bottom of tank. This connection may require adjustment or tightening. It is also possible that this nut requires replacement. In addition, the toilet may be leaking between the tank and bowl, or between the toilet and the floor. Listen to this Handyguys episode for their recommendation on fixing this issue. Hint: mopping up the floor only addresses the symptom, not the cause!

Using a “closet auger” to clear a clogThe the other major quandary we all face is the clogged toilet. The Handyguys provide some suggestions for toilets that always seem to clog.

Feel free to use the comment feature below to post your specific toilet questions.

8 thoughts on “How To Repair A Toilet

  1. How timely your post is. I’ll be sure to print this out and give it to the not-so-handy guy in my house so he can fix our awful toilet! Hopefully we won’t have any more waterfalls in the kitchen.
    Thanks and I love the sight!

  2. Pingback: On a traditional, low-flow toilet, can a leaky flapper cause a poor flush? | Plumbing in Seattle
  3. Pingback: air in the lines
    1. Maybe – Different types of flappers might work on different types of toilets. Some toilets use a dropping ball type of setup versus a flapper. Also, fluid master sells a flapper with a new base that repairs cracked, leaky or uneven flapper bases.

  4. What do I do if no water is coming in from the water valve. You can turn it on and off and nothing…
    Thank you for your amazing site

    1. It could be a faulty valve. I assume you mean the shutoff valve. Turn off main water supply and then replace the valve. It may require soldering or it may screw off depending how it was installed originally.

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